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Date:      Mon, 5 Feb 2024 00:30:01 GMT
From:      Philip Paeps <philip@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org
Subject:   git: 26fe22019cb2 - stable/14 - contrib/tzdata: import tzdata 2024a
Message-ID:  <202402050030.4150U1Mo040586@gitrepo.freebsd.org>

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The branch stable/14 has been updated by philip:

URL: https://cgit.FreeBSD.org/src/commit/?id=26fe22019cb244aaaf8f96218e6e74641157e204

commit 26fe22019cb244aaaf8f96218e6e74641157e204
Author:     Philip Paeps <philip@FreeBSD.org>
AuthorDate: 2024-02-02 02:01:39 +0000
Commit:     Philip Paeps <philip@FreeBSD.org>
CommitDate: 2024-02-05 00:28:54 +0000

    contrib/tzdata: import tzdata 2024a
    
    Changes: https://github.com/eggert/tz/blob/2024a/NEWS
    
    (cherry picked from commit 2723c7ffb7f729a1d3f7c59e7db48b0edf3d30a6)
---
 contrib/tzdata/Makefile          |  53 ++++--
 contrib/tzdata/NEWS              |  68 +++++++
 contrib/tzdata/africa            |   8 +-
 contrib/tzdata/asia              | 174 +++++++++++-------
 contrib/tzdata/australasia       |  14 +-
 contrib/tzdata/checknow.awk      |   2 +-
 contrib/tzdata/etcetera          |   2 +-
 contrib/tzdata/europe            |  29 ++-
 contrib/tzdata/leap-seconds.list | 373 +++++++++++++--------------------------
 contrib/tzdata/leapseconds       |  19 +-
 contrib/tzdata/leapseconds.awk   |  11 +-
 contrib/tzdata/northamerica      |  29 +--
 contrib/tzdata/southamerica      |   5 +-
 contrib/tzdata/theory.html       |  37 ++--
 contrib/tzdata/version           |   2 +-
 contrib/tzdata/zishrink.awk      |  98 ++++++----
 contrib/tzdata/zonenow.tab       |   4 +-
 17 files changed, 507 insertions(+), 421 deletions(-)

diff --git a/contrib/tzdata/Makefile b/contrib/tzdata/Makefile
index 4e45f93b915c..d48354c72df4 100644
--- a/contrib/tzdata/Makefile
+++ b/contrib/tzdata/Makefile
@@ -53,7 +53,7 @@ DATAFORM=		main
 
 LOCALTIME=	Factory
 
-# The POSIXRULES macro controls interpretation of POSIX-like TZ
+# The POSIXRULES macro controls interpretation of POSIX-2017.1-like TZ
 # settings like TZ='EET-2EEST' that lack DST transition rules.
 # If POSIXRULES is '-', no template is installed; this is the default.
 # Any other value for POSIXRULES is obsolete and should not be relied on, as:
@@ -274,7 +274,7 @@ LDLIBS=
 #  -DTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory;
 #	the default is system-supplied, typically "/usr/lib/locale"
 #  -DTZDEFRULESTRING=\",date/time,date/time\" to default to the specified
-#	DST transitions for POSIX-style TZ strings lacking them,
+#	DST transitions for POSIX.1-2017-style TZ strings lacking them,
 #	in the usual case where POSIXRULES is '-'.  If not specified,
 #	TZDEFRULESTRING defaults to US rules for future DST transitions.
 #	This mishandles some past timestamps, as US DST rules have changed.
@@ -340,9 +340,10 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # guess TM_GMTOFF from other macros; define NO_TM_GMTOFF to suppress this.
 # Similarly, if your system has a "zone abbreviation" field, define
 #	-DTM_ZONE=tm_zone
-# and define NO_TM_ZONE to suppress any guessing.  Although these two fields
-# not required by POSIX, a future version of POSIX is planned to require them
-# and they are widely available on GNU/Linux and BSD systems.
+# and define NO_TM_ZONE to suppress any guessing.
+# Although these two fields are not required by POSIX.1-2017,
+# POSIX 202x/D4 requires them and they are widely available
+# on GNU/Linux and BSD systems.
 #
 # The next batch of options control support for external variables
 # exported by tzcode.  In practice these variables are less useful
@@ -352,7 +353,7 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # #	-DHAVE_TZNAME=0 # do not support "tzname"
 # #	-DHAVE_TZNAME=1 # support "tzname", which is defined by system library
 # #	-DHAVE_TZNAME=2 # support and define "tzname"
-# # to the "CFLAGS=" line.  "tzname" is required by POSIX 1988 and later.
+# # to the "CFLAGS=" line.  "tzname" is required by POSIX.1-1988 and later.
 # # If not defined, the code attempts to guess HAVE_TZNAME from other macros.
 # # Warning: unless time_tz is also defined, HAVE_TZNAME=1 can cause
 # # crashes when combined with some platforms' standard libraries,
@@ -362,8 +363,8 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # #	-DUSG_COMPAT=0 # do not support
 # #	-DUSG_COMPAT=1 # support, and variables are defined by system library
 # #	-DUSG_COMPAT=2 # support and define variables
-# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by
-# # Unix Systems Group code and are required by POSIX 2008 (with XSI) and later.
+# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by Unix
+# # Systems Group code and are required by POSIX.1-2008 and later (with XSI).
 # # If not defined, the code attempts to guess USG_COMPAT from other macros.
 # #
 # # To support the external variable "altzone", add
@@ -427,7 +428,7 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 
 # The name of a POSIX-like library archiver, its flags, C compiler,
 # linker flags, and 'make' utility.  Ordinarily the defaults suffice.
-# The commented-out values are the defaults specified by POSIX 202x/D3.
+# The commented-out values are the defaults specified by POSIX.1-202x/D4.
 #AR = ar
 #ARFLAGS = -rv
 #CC = c17
@@ -439,6 +440,12 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 
 LEAPSECONDS=
 
+# Where to fetch leap-seconds.list from.
+leaplist_URI = \
+  https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list
+# The file is generated by the IERS Earth Orientation Centre, in Paris.
+leaplist_TZ = Europe/Paris
+
 # The zic command and its arguments.
 
 zic=		./zic
@@ -471,7 +478,8 @@ AWK=		awk
 # is typically nicer if it works.
 KSHELL=		/bin/bash
 
-# Name of curl <https://curl.haxx.se/>, used for HTML validation.
+# Name of curl <https://curl.haxx.se/>, used for HTML validation
+# and to fetch leap-seconds.list from upstream.
 CURL=		curl
 
 # Name of GNU Privacy Guard <https://gnupg.org/>, used to sign distributions.
@@ -718,6 +726,28 @@ leapseconds:	$(LEAP_DEPS)
 		  -f leapseconds.awk leap-seconds.list >$@.out
 		mv $@.out $@
 
+# Awk script to extract a Git-style author from leap-seconds.list comments.
+EXTRACT_AUTHOR = \
+  author_line { sub(/^.[[:space:]]*/, ""); \
+      sub(/:[[:space:]]*/, " <"); \
+      printf "%s>\n", $$0; \
+      success = 1; \
+      exit \
+  } \
+  /Questions or comments to:/ { author_line = 1 } \
+  END { exit !success }
+
+# Fetch leap-seconds.list from upstream.
+fetch-leap-seconds.list:
+		$(CURL) -OR $(leaplist_URI)
+
+# Fetch leap-seconds.list from upstream and commit it to the local repository.
+commit-leap-seconds.list: fetch-leap-seconds.list
+		author=$$($(AWK) '$(EXTRACT_AUTHOR)' leap-seconds.list) && \
+		date=$$(TZ=$(leaplist_TZ) stat -c%y leap-seconds.list) && \
+		git commit --author="$$author" --date="$$date" -m'make $@' \
+		  leap-seconds.list
+
 # Arguments to pass to submakes of install_data.
 # They can be overridden by later submake arguments.
 INSTALLARGS = \
@@ -1315,7 +1345,8 @@ zic.o:		private.h tzfile.h tzdir.h version.h
 .PHONY: ALL INSTALL all
 .PHONY: check check_mild check_time_t_alternatives
 .PHONY: check_web check_zishrink
-.PHONY: clean clean_misc dummy.zd force_tzs
+.PHONY: clean clean_misc commit-leap-seconds.list dummy.zd
+.PHONY: fetch-leap-seconds.list force_tzs
 .PHONY: install install_data maintainer-clean names
 .PHONY: posix_only posix_right public
 .PHONY: rearguard_signatures rearguard_signatures_version
diff --git a/contrib/tzdata/NEWS b/contrib/tzdata/NEWS
index 031ba6a8a250..d407342a50e6 100644
--- a/contrib/tzdata/NEWS
+++ b/contrib/tzdata/NEWS
@@ -1,5 +1,73 @@
 News for the tz database
 
+Release 2024a - 2024-02-01 09:28:56 -0800
+
+  Briefly:
+    Kazakhstan unifies on UTC+5 beginning 2024-03-01.
+    Palestine springs forward a week later after Ramadan.
+    zic no longer pretends to support indefinite-past DST.
+    localtime no longer mishandles Ciudad Juárez in 2422.
+
+  Changes to future timestamps
+
+    Kazakhstan unifies on UTC+5.  This affects Asia/Almaty and
+    Asia/Qostanay which together represent the eastern portion of the
+    country that will transition from UTC+6 on 2024-03-01 at 00:00 to
+    join the western portion.  (Thanks to Zhanbolat Raimbekov.)
+
+    Palestine springs forward a week later than previously predicted
+    in 2024 and 2025.  (Thanks to Heba Hamad.)  Change spring-forward
+    predictions to the second Saturday after Ramadan, not the first;
+    this also affects other predictions starting in 2039.
+
+  Changes to past timestamps
+
+    Asia/Ho_Chi_Minh's 1955-07-01 transition occurred at 01:00
+    not 00:00.  (Thanks to Đoàn Trần Công Danh.)
+
+    From 1947 through 1949, Toronto's transitions occurred at 02:00
+    not 00:00.  (Thanks to Chris Walton.)
+
+    In 1911 Miquelon adopted standard time on June 15, not May 15.
+
+  Changes to code
+
+    The FROM and TO columns of Rule lines can no longer be "minimum"
+    or an abbreviation of "minimum", because TZif files do not support
+    DST rules that extend into the indefinite past - although these
+    rules were supported when TZif files had only 32-bit data, this
+    stopped working when 64-bit TZif files were introduced in 1995.
+    This should not be a problem for realistic data, since DST was
+    first used in the 20th century.  As a transition aid, FROM columns
+    like "minimum" are now diagnosed and then treated as if they were
+    the year 1900; this should suffice for TZif files on old systems
+    with only 32-bit time_t, and it is more compatible with bugs in
+    2023c-and-earlier localtime.c.  (Problem reported by Yoshito
+    Umaoka.)
+
+    localtime and related functions no longer mishandle some
+    timestamps that occur about 400 years after a switch to a time
+    zone with a DST schedule.  In 2023d data this problem was visible
+    for some timestamps in November 2422, November 2822, etc. in
+    America/Ciudad_Juarez.  (Problem reported by Gilmore Davidson.)
+
+    strftime %s now uses tm_gmtoff if available.  (Problem and draft
+    patch reported by Dag-Erling Smørgrav.)
+
+  Changes to build procedure
+
+    The leap-seconds.list file is now copied from the IERS instead of
+    from its downstream counterpart at NIST, as the IERS version is
+    now in the public domain too and tends to be more up-to-date.
+    (Thanks to Martin Burnicki for liaisoning with the IERS.)
+
+  Changes to documentation
+
+    The strftime man page documents which struct tm members affect
+    which conversion specs, and that tzset is called.  (Problems
+    reported by Robert Elz and Steve Summit.)
+
+
 Release 2023d - 2023-12-21 20:02:24 -0800
 
   Briefly:
diff --git a/contrib/tzdata/africa b/contrib/tzdata/africa
index 6fae18c0979f..92d823a0515c 100644
--- a/contrib/tzdata/africa
+++ b/contrib/tzdata/africa
@@ -30,6 +30,10 @@
 # Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94.
 # https://www.jstor.org/stable/1774359
 #
+# For the 1911/1912 establishment of standard time in French possessions, see:
+# Société Française de Physique, Recueil de constantes physiques (1913),
+# page 752, 18b.
+#
 # European-style abbreviations are commonly used along the Mediterranean.
 # For sub-Saharan Africa abbreviations were less standardized.
 # Previous editions of this database used WAT, CAT, SAT, and EAT
@@ -113,7 +117,7 @@ Zone Atlantic/Cape_Verde -1:34:04 -	LMT	1912 Jan 01  2:00u # Praia
 
 # Chad
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Africa/Ndjamena	1:00:12 -	LMT	1912        # N'Djamena
+Zone	Africa/Ndjamena	1:00:12 -	LMT	1912 Jan  1 # N'Djamena
 			1:00	-	WAT	1979 Oct 14
 			1:00	1:00	WAST	1980 Mar  8
 			1:00	-	WAT
@@ -139,7 +143,7 @@ Zone	Africa/Ndjamena	1:00:12 -	LMT	1912        # N'Djamena
 #	Inaccessible, Nightingale: uninhabited
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Africa/Abidjan	-0:16:08 -	LMT	1912
+Zone	Africa/Abidjan	-0:16:08 -	LMT	1912 Jan  1
 			 0:00	-	GMT
 
 ###############################################################################
diff --git a/contrib/tzdata/asia b/contrib/tzdata/asia
index 04526c196931..05683b9ebaa3 100644
--- a/contrib/tzdata/asia
+++ b/contrib/tzdata/asia
@@ -2457,18 +2457,33 @@ Zone	Asia/Amman	2:23:44 -	LMT	1931
 # effective December 21st, 2018....
 # http://adilet.zan.kz/rus/docs/P1800000817 (russian language).
 
+# From Zhanbolat Raimbekov (2024-01-19):
+# Kazakhstan (all parts) switching to UTC+5 on March 1, 2024
+# https://www.gov.kz/memleket/entities/mti/press/news/details/688998?lang=ru
+# [in Russian]
+# (2024-01-20): https://primeminister.kz/ru/decisions/19012024-20
+#
+# From Alexander Krivenyshev (2024-01-19):
+# According to a different news and the official web site for the Ministry of
+# Trade and Integration of the Republic of Kazakhstan:
+# https://en.inform.kz/news/kazakhstan-to-switch-to-single-hour-zone-mar-1-54ad0b/
+
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 #
 # Almaty (formerly Alma-Ata), representing most locations in Kazakhstan
-# This includes KZ-AKM, KZ-ALA, KZ-ALM, KZ-AST, KZ-BAY, KZ-VOS, KZ-ZHA,
-# KZ-KAR, KZ-SEV, KZ-PAV, and KZ-YUZ.
+# This includes Abai/Abay (ISO 3166-2 code KZ-10), Aqmola/Akmola (KZ-11),
+# Almaty (KZ-19), Almaty city (KZ-75), Astana city (KZ-71),
+# East Kazkhstan (KZ-63), Jambyl/Zhambyl (KZ-31), Jetisu/Zhetysu (KZ-33),
+# Karaganda (KZ-35), North Kazakhstan (KZ-59), Pavlodar (KZ-55),
+# Shyumkent city (KZ-79), Turkistan (KZ-61), and Ulytau (KZ-62).
 Zone	Asia/Almaty	5:07:48 -	LMT	1924 May  2 # or Alma-Ata
 			5:00	-	+05	1930 Jun 21
 			6:00 RussiaAsia +06/+07	1991 Mar 31  2:00s
 			5:00 RussiaAsia	+05/+06	1992 Jan 19  2:00s
 			6:00 RussiaAsia	+06/+07	2004 Oct 31  2:00s
-			6:00	-	+06
-# Qyzylorda (aka Kyzylorda, Kizilorda, Kzyl-Orda, etc.) (KZ-KZY)
+			6:00	-	+06	2024 Mar  1  0:00
+			5:00	-	+05
+# Qyzylorda (aka Kyzylorda, Kizilorda, Kzyl-Orda, etc.) (KZ-43)
 Zone	Asia/Qyzylorda	4:21:52 -	LMT	1924 May  2
 			4:00	-	+04	1930 Jun 21
 			5:00	-	+05	1981 Apr  1
@@ -2481,8 +2496,7 @@ Zone	Asia/Qyzylorda	4:21:52 -	LMT	1924 May  2
 			5:00 RussiaAsia	+05/+06	2004 Oct 31  2:00s
 			6:00	-	+06	2018 Dec 21  0:00
 			5:00	-	+05
-#
-# Qostanay (aka Kostanay, Kustanay) (KZ-KUS)
+# Qostanay (aka Kostanay, Kustanay) (KZ-39)
 # The 1991/2 rules are unclear partly because of the 1997 Turgai
 # reorganization.
 Zone	Asia/Qostanay	4:14:28 -	LMT	1924 May  2
@@ -2493,9 +2507,9 @@ Zone	Asia/Qostanay	4:14:28 -	LMT	1924 May  2
 			5:00 RussiaAsia	+05/+06	1991 Mar 31  2:00s
 			4:00 RussiaAsia	+04/+05	1992 Jan 19  2:00s
 			5:00 RussiaAsia	+05/+06	2004 Oct 31  2:00s
-			6:00	-	+06
-
-# Aqtöbe (aka Aktobe, formerly Aktyubinsk) (KZ-AKT)
+			6:00	-	+06	2024 Mar  1  0:00
+			5:00	-	+05
+# Aqtöbe (aka Aktobe, formerly Aktyubinsk) (KZ-15)
 Zone	Asia/Aqtobe	3:48:40	-	LMT	1924 May  2
 			4:00	-	+04	1930 Jun 21
 			5:00	-	+05	1981 Apr  1
@@ -2505,7 +2519,7 @@ Zone	Asia/Aqtobe	3:48:40	-	LMT	1924 May  2
 			4:00 RussiaAsia	+04/+05	1992 Jan 19  2:00s
 			5:00 RussiaAsia	+05/+06	2004 Oct 31  2:00s
 			5:00	-	+05
-# Mangghystaū (KZ-MAN)
+# Mangghystaū (KZ-47)
 # Aqtau was not founded until 1963, but it represents an inhabited region,
 # so include timestamps before 1963.
 Zone	Asia/Aqtau	3:21:04	-	LMT	1924 May  2
@@ -2517,7 +2531,7 @@ Zone	Asia/Aqtau	3:21:04	-	LMT	1924 May  2
 			5:00 RussiaAsia	+05/+06	1994 Sep 25  2:00s
 			4:00 RussiaAsia	+04/+05	2004 Oct 31  2:00s
 			5:00	-	+05
-# Atyraū (KZ-ATY) is like Mangghystaū except it switched from
+# Atyraū (KZ-23) is like Mangghystaū except it switched from
 # +04/+05 to +05/+06 in spring 1999, not fall 1994.
 Zone	Asia/Atyrau	3:27:44	-	LMT	1924 May  2
 			3:00	-	+03	1930 Jun 21
@@ -2528,7 +2542,7 @@ Zone	Asia/Atyrau	3:27:44	-	LMT	1924 May  2
 			5:00 RussiaAsia	+05/+06	1999 Mar 28  2:00s
 			4:00 RussiaAsia	+04/+05	2004 Oct 31  2:00s
 			5:00	-	+05
-# West Kazakhstan (KZ-ZAP)
+# West Kazakhstan (KZ-27)
 # From Paul Eggert (2016-03-18):
 # The 1989 transition is from USSR act No. 227 (1989-03-14).
 Zone	Asia/Oral	3:25:24	-	LMT	1924 May  2 # or Ural'sk
@@ -3430,19 +3444,26 @@ Zone	Asia/Karachi	4:28:12 -	LMT	1907
 # ... winter time will begin in Palestine from Saturday 10-28-2023,
 # 02:00 AM by 60 minutes back.
 #
-# From Paul Eggert (2023-03-22):
+# From Heba Hamad (2024-01-25):
+# the summer time for the years 2024,2025 will begin in Palestine
+# from Saturday at 02:00 AM by 60 minutes forward as shown below:
+# year date
+# 2024 2024-04-20
+# 2025 2025-04-12
+#
+# From Paul Eggert (2024-01-25):
 # For now, guess that spring and fall transitions will normally
 # continue to use 2022's rules, that during DST Palestine will switch
 # to standard time at 02:00 the last Saturday before Ramadan and back
-# to DST at 02:00 the first Saturday after Ramadan, and that
+# to DST at 02:00 the second Saturday after Ramadan, and that
 # if the normal spring-forward or fall-back transition occurs during
 # Ramadan the former is delayed and the latter advanced.
 # To implement this, I predicted Ramadan-oriented transition dates for
-# 2023 through 2086 by running the following program under GNU Emacs 28.2,
+# 2026 through 2086 by running the following program under GNU Emacs 29.2,
 # with the results integrated by hand into the table below.
 # Predictions after 2086 are approximated without Ramadan.
 #
-# (let ((islamic-year 1444))
+# (let ((islamic-year 1447))
 #   (require 'cal-islam)
 #   (while (< islamic-year 1510)
 #     (let ((a (calendar-islamic-to-absolute (list 9 1 islamic-year)))
@@ -3451,6 +3472,7 @@ Zone	Asia/Karachi	4:28:12 -	LMT	1907
 #       (while (/= saturday (mod (setq a (1- a)) 7)))
 #       (while (/= saturday (mod b 7))
 #         (setq b (1+ b)))
+#       (setq b (+ 7 b))
 #       (setq a (calendar-gregorian-from-absolute a))
 #       (setq b (calendar-gregorian-from-absolute b))
 #       (insert
@@ -3501,84 +3523,84 @@ Rule Palestine	2021	only	-	Oct	29	1:00	0	-
 Rule Palestine	2022	only	-	Mar	27	0:00	1:00	S
 Rule Palestine	2022	2035	-	Oct	Sat<=30	2:00	0	-
 Rule Palestine	2023	only	-	Apr	29	2:00	1:00	S
-Rule Palestine	2024	only	-	Apr	13	2:00	1:00	S
-Rule Palestine	2025	only	-	Apr	 5	2:00	1:00	S
+Rule Palestine	2024	only	-	Apr	20	2:00	1:00	S
+Rule Palestine	2025	only	-	Apr	12	2:00	1:00	S
 Rule Palestine	2026	2054	-	Mar	Sat<=30	2:00	1:00	S
 Rule Palestine	2036	only	-	Oct	18	2:00	0	-
 Rule Palestine	2037	only	-	Oct	10	2:00	0	-
 Rule Palestine	2038	only	-	Sep	25	2:00	0	-
 Rule Palestine	2039	only	-	Sep	17	2:00	0	-
-Rule Palestine	2039	only	-	Oct	22	2:00	1:00	S
-Rule Palestine	2039	2067	-	Oct	Sat<=30	2:00	0	-
 Rule Palestine	2040	only	-	Sep	 1	2:00	0	-
-Rule Palestine	2040	only	-	Oct	13	2:00	1:00	S
+Rule Palestine	2040	only	-	Oct	20	2:00	1:00	S
+Rule Palestine	2040	2067	-	Oct	Sat<=30	2:00	0	-
 Rule Palestine	2041	only	-	Aug	24	2:00	0	-
-Rule Palestine	2041	only	-	Sep	28	2:00	1:00	S
+Rule Palestine	2041	only	-	Oct	 5	2:00	1:00	S
 Rule Palestine	2042	only	-	Aug	16	2:00	0	-
-Rule Palestine	2042	only	-	Sep	20	2:00	1:00	S
+Rule Palestine	2042	only	-	Sep	27	2:00	1:00	S
 Rule Palestine	2043	only	-	Aug	 1	2:00	0	-
-Rule Palestine	2043	only	-	Sep	12	2:00	1:00	S
+Rule Palestine	2043	only	-	Sep	19	2:00	1:00	S
 Rule Palestine	2044	only	-	Jul	23	2:00	0	-
-Rule Palestine	2044	only	-	Aug	27	2:00	1:00	S
+Rule Palestine	2044	only	-	Sep	 3	2:00	1:00	S
 Rule Palestine	2045	only	-	Jul	15	2:00	0	-
-Rule Palestine	2045	only	-	Aug	19	2:00	1:00	S
+Rule Palestine	2045	only	-	Aug	26	2:00	1:00	S
 Rule Palestine	2046	only	-	Jun	30	2:00	0	-
-Rule Palestine	2046	only	-	Aug	11	2:00	1:00	S
+Rule Palestine	2046	only	-	Aug	18	2:00	1:00	S
 Rule Palestine	2047	only	-	Jun	22	2:00	0	-
-Rule Palestine	2047	only	-	Jul	27	2:00	1:00	S
+Rule Palestine	2047	only	-	Aug	 3	2:00	1:00	S
 Rule Palestine	2048	only	-	Jun	 6	2:00	0	-
-Rule Palestine	2048	only	-	Jul	18	2:00	1:00	S
+Rule Palestine	2048	only	-	Jul	25	2:00	1:00	S
 Rule Palestine	2049	only	-	May	29	2:00	0	-
-Rule Palestine	2049	only	-	Jul	 3	2:00	1:00	S
+Rule Palestine	2049	only	-	Jul	10	2:00	1:00	S
 Rule Palestine	2050	only	-	May	21	2:00	0	-
-Rule Palestine	2050	only	-	Jun	25	2:00	1:00	S
+Rule Palestine	2050	only	-	Jul	 2	2:00	1:00	S
 Rule Palestine	2051	only	-	May	 6	2:00	0	-
-Rule Palestine	2051	only	-	Jun	17	2:00	1:00	S
+Rule Palestine	2051	only	-	Jun	24	2:00	1:00	S
 Rule Palestine	2052	only	-	Apr	27	2:00	0	-
-Rule Palestine	2052	only	-	Jun	 1	2:00	1:00	S
+Rule Palestine	2052	only	-	Jun	 8	2:00	1:00	S
 Rule Palestine	2053	only	-	Apr	12	2:00	0	-
-Rule Palestine	2053	only	-	May	24	2:00	1:00	S
+Rule Palestine	2053	only	-	May	31	2:00	1:00	S
 Rule Palestine	2054	only	-	Apr	 4	2:00	0	-
-Rule Palestine	2054	only	-	May	16	2:00	1:00	S
-Rule Palestine	2055	only	-	May	 1	2:00	1:00	S
-Rule Palestine	2056	only	-	Apr	22	2:00	1:00	S
-Rule Palestine	2057	only	-	Apr	 7	2:00	1:00	S
-Rule Palestine	2058	max	-	Mar	Sat<=30	2:00	1:00	S
+Rule Palestine	2054	only	-	May	23	2:00	1:00	S
+Rule Palestine	2055	only	-	May	 8	2:00	1:00	S
+Rule Palestine	2056	only	-	Apr	29	2:00	1:00	S
+Rule Palestine	2057	only	-	Apr	14	2:00	1:00	S
+Rule Palestine	2058	only	-	Apr	 6	2:00	1:00	S
+Rule Palestine	2059	max	-	Mar	Sat<=30	2:00	1:00	S
 Rule Palestine	2068	only	-	Oct	20	2:00	0	-
 Rule Palestine	2069	only	-	Oct	12	2:00	0	-
 Rule Palestine	2070	only	-	Oct	 4	2:00	0	-
 Rule Palestine	2071	only	-	Sep	19	2:00	0	-
 Rule Palestine	2072	only	-	Sep	10	2:00	0	-
-Rule Palestine	2072	only	-	Oct	15	2:00	1:00	S
+Rule Palestine	2072	only	-	Oct	22	2:00	1:00	S
 Rule Palestine	2072	max	-	Oct	Sat<=30	2:00	0	-
 Rule Palestine	2073	only	-	Sep	 2	2:00	0	-
-Rule Palestine	2073	only	-	Oct	 7	2:00	1:00	S
+Rule Palestine	2073	only	-	Oct	14	2:00	1:00	S
 Rule Palestine	2074	only	-	Aug	18	2:00	0	-
-Rule Palestine	2074	only	-	Sep	29	2:00	1:00	S
+Rule Palestine	2074	only	-	Oct	 6	2:00	1:00	S
 Rule Palestine	2075	only	-	Aug	10	2:00	0	-
-Rule Palestine	2075	only	-	Sep	14	2:00	1:00	S
+Rule Palestine	2075	only	-	Sep	21	2:00	1:00	S
 Rule Palestine	2076	only	-	Jul	25	2:00	0	-
-Rule Palestine	2076	only	-	Sep	 5	2:00	1:00	S
+Rule Palestine	2076	only	-	Sep	12	2:00	1:00	S
 Rule Palestine	2077	only	-	Jul	17	2:00	0	-
-Rule Palestine	2077	only	-	Aug	28	2:00	1:00	S
+Rule Palestine	2077	only	-	Sep	 4	2:00	1:00	S
 Rule Palestine	2078	only	-	Jul	 9	2:00	0	-
-Rule Palestine	2078	only	-	Aug	13	2:00	1:00	S
+Rule Palestine	2078	only	-	Aug	20	2:00	1:00	S
 Rule Palestine	2079	only	-	Jun	24	2:00	0	-
-Rule Palestine	2079	only	-	Aug	 5	2:00	1:00	S
+Rule Palestine	2079	only	-	Aug	12	2:00	1:00	S
 Rule Palestine	2080	only	-	Jun	15	2:00	0	-
-Rule Palestine	2080	only	-	Jul	20	2:00	1:00	S
+Rule Palestine	2080	only	-	Jul	27	2:00	1:00	S
 Rule Palestine	2081	only	-	Jun	 7	2:00	0	-
-Rule Palestine	2081	only	-	Jul	12	2:00	1:00	S
+Rule Palestine	2081	only	-	Jul	19	2:00	1:00	S
 Rule Palestine	2082	only	-	May	23	2:00	0	-
-Rule Palestine	2082	only	-	Jul	 4	2:00	1:00	S
+Rule Palestine	2082	only	-	Jul	11	2:00	1:00	S
 Rule Palestine	2083	only	-	May	15	2:00	0	-
-Rule Palestine	2083	only	-	Jun	19	2:00	1:00	S
+Rule Palestine	2083	only	-	Jun	26	2:00	1:00	S
 Rule Palestine	2084	only	-	Apr	29	2:00	0	-
-Rule Palestine	2084	only	-	Jun	10	2:00	1:00	S
+Rule Palestine	2084	only	-	Jun	17	2:00	1:00	S
 Rule Palestine	2085	only	-	Apr	21	2:00	0	-
-Rule Palestine	2085	only	-	Jun	 2	2:00	1:00	S
+Rule Palestine	2085	only	-	Jun	 9	2:00	1:00	S
 Rule Palestine	2086	only	-	Apr	13	2:00	0	-
-Rule Palestine	2086	only	-	May	18	2:00	1:00	S
+Rule Palestine	2086	only	-	May	25	2:00	1:00	S
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Gaza	2:17:52	-	LMT	1900 Oct
@@ -3606,7 +3628,7 @@ Zone	Asia/Hebron	2:20:23	-	LMT	1900 Oct
 
 # Philippines
 
-# From Paul Eggert (2018-11-18):
+# From Paul Eggert (2024-01-21):
 # The Spanish initially used American (west-of-Greenwich) time.
 # It is unknown what time Manila kept when the British occupied it from
 # 1762-10-06 through 1764-04; for now assume it kept American time.
@@ -3614,7 +3636,7 @@ Zone	Asia/Hebron	2:20:23	-	LMT	1900 Oct
 # Philippines, issued a proclamation announcing that 1844-12-30 was to
 # be immediately followed by 1845-01-01; see R.H. van Gent's
 # History of the International Date Line
-# https://www.staff.science.uu.nl/~gent0113/idl/idl_philippines.htm
+# https://webspace.science.uu.nl/~gent0113/idl/idl_philippines.htm
 # The rest of the data entries are from Shanks & Pottenger.
 
 # From Jesper Nørgaard Welen (2006-04-26):
@@ -4041,7 +4063,8 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 # The English-language name of Vietnam's most populous city is "Ho Chi Minh
 # City"; use Ho_Chi_Minh below to avoid a name of more than 14 characters.
 
-# From Paul Eggert (2022-07-27) after a 2014 heads-up from Trần Ngọc Quân:
+# From Paul Eggert (2024-01-14) after a 2014 heads-up from Trần Ngọc Quân
+# and a 2024-01-14 heads-up from Đoàn Trần Công Danh:
 # Trần Tiến Bình's authoritative book "Lịch Việt Nam: thế kỷ XX-XXI (1901-2100)"
 # (Nhà xuất bản Văn Hoá - Thông Tin, Hanoi, 2005), pp 49-50,
 # is quoted verbatim in:
@@ -4071,14 +4094,35 @@ Zone	Asia/Tashkent	4:37:11 -	LMT	1924 May  2
 #
 # Trần cites the following sources; it's unclear which supplied the info above.
 #
-# Hoàng Xuân Hãn: "Lịch và lịch Việt Nam". Tập san Khoa học Xã hội,
-# No. 9, Paris, February 1982.
+#   Hoàng Xuân Hãn: "Lịch và lịch Việt Nam". Tập san Khoa học Xã hội,
+#   No. 9, Paris, February 1982.
+#
+#   Lê Thành Lân: "Lịch và niên biểu lịch sử hai mươi thế kỷ (0001-2010)",
+#   NXB Thống kê, Hanoi, 2000.
 #
-# Lê Thành Lân: "Lịch và niên biểu lịch sử hai mươi thế kỷ (0001-2010)",
-# NXB Thống kê, Hanoi, 2000.
+#   Lê Thành Lân: "Lịch hai thế kỷ (1802-2010) và các lịch vĩnh cửu",
+#   NXB Thuận Hoá, Huế, 1995.
 #
-# Lê Thành Lân: "Lịch hai thế kỷ (1802-2010) và các lịch vĩnh cửu",
-# NXB Thuận Hoá, Huế, 1995.
+# Here is the decision for the September 1945 transition:
+# Võ Nguyên Giáp, Việt Nam Dân Quốc Công Báo, No. 1 (1945-09-29), page 13
+# http://baochi.nlv.gov.vn/baochi/cgi-bin/baochi?a=d&d=JwvzO19450929.2.5&dliv=none
+# It says that on 1945-09-01 at 24:00, Vietnam moved back two hours, to +07.
+# It also mentions a 1945-03-29 decree (by a Japanese Goveror-General)
+# to set the time zone to +09, but does not say whether that decree
+# merely legalized an earlier change to +09.
+#
+# July 1955 transition:
+# Ngô Đình Diệm, Công Báo Việt Nam, No. 92 (1955-07-02), page 1780-1781
+# Ordinance (Dụ) No. 46 (1955-06-25)
+# http://ddsnext.crl.edu/titles/32341#?c=0&m=29&s=0&cv=4&r=0&xywh=-89%2C342%2C1724%2C1216
+# It says that on 1955-07-01 at 01:00, South Vietnam moved back 1 hour (to +07).
+#
+# December 1959 transition:
+# Ngô Đình Diệm, Công Báo Việt Nam Cộng Hòa, 1960 part 1 (1960-01-02), page 62
+# Decree (Sắc lệnh) No. 362-TTP (1959-12-30)
+# http://ddsnext.crl.edu/titles/32341#?c=0&m=138&s=0&cv=793&r=0&xywh=-54%2C1504%2C1705%2C1202
+# It says that on 1959-12-31 at 23:00, South Vietnam moved forward 1 hour (to +08).
+
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 		#STDOFF	7:06:30.13
@@ -4086,9 +4130,9 @@ Zone Asia/Ho_Chi_Minh	7:06:30 -	LMT	1906 Jul  1
 			7:06:30	-	PLMT	1911 May  1 # Phù Liễn MT
 			7:00	-	+07	1942 Dec 31 23:00
 			8:00	-	+08	1945 Mar 14 23:00
-			9:00	-	+09	1945 Sep  2
+			9:00	-	+09	1945 Sep  1 24:00
 			7:00	-	+07	1947 Apr  1
-			8:00	-	+08	1955 Jul  1
+			8:00	-	+08	1955 Jul  1 01:00
 			7:00	-	+07	1959 Dec 31 23:00
 			8:00	-	+08	1975 Jun 13
 			7:00	-	+07
diff --git a/contrib/tzdata/australasia b/contrib/tzdata/australasia
index dc98c1e2de17..0e9c2592e4be 100644
--- a/contrib/tzdata/australasia
+++ b/contrib/tzdata/australasia
@@ -420,11 +420,11 @@ Zone	Pacific/Fiji	11:55:44 -	LMT	1915 Oct 26 # Suva
 
 # French Polynesia
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Pacific/Gambier	 -8:59:48 -	LMT	1912 Oct # Rikitea
+Zone	Pacific/Gambier	 -8:59:48 -	LMT	1912 Oct  1 # Rikitea
 			 -9:00	-	-09
-Zone	Pacific/Marquesas -9:18:00 -	LMT	1912 Oct
+Zone	Pacific/Marquesas -9:18:00 -	LMT	1912 Oct  1
 			 -9:30	-	-0930
-Zone	Pacific/Tahiti	 -9:58:16 -	LMT	1912 Oct # Papeete
+Zone	Pacific/Tahiti	 -9:58:16 -	LMT	1912 Oct  1 # Papeete
 			-10:00	-	-10
 # Clipperton (near North America) is administered from French Polynesia;
 # it is uninhabited.
@@ -802,7 +802,7 @@ Zone Pacific/Apia	 12:33:04 -	LMT	1892 Jul  5
 # Solomon Is
 # excludes Bougainville, for which see Papua New Guinea
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone Pacific/Guadalcanal 10:39:48 -	LMT	1912 Oct # Honiara
+Zone Pacific/Guadalcanal 10:39:48 -	LMT	1912 Oct  1 # Honiara
 			11:00	-	+11
 
 # Tokelau
@@ -963,6 +963,10 @@ Zone	Pacific/Efate	11:13:16 -	LMT	1912 Jan 13 # Vila
 # Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94.
 # https://www.jstor.org/stable/1774359
 #
+# For the 1911/1912 establishment of standard time in French possessions, see:
+# Société Française de Physique, Recueil de constantes physiques (1913),
+# page 752, 18b.
+#
 # A reliable and entertaining source about time zones is
 # Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
 #
@@ -2039,7 +2043,7 @@ Zone	Pacific/Efate	11:13:16 -	LMT	1912 Jan 13 # Vila
 # ordaining - by a masterpiece of diplomatic flattery - that
 # the Fourth of July should be celebrated twice in that year."
 # This happened in 1892, according to the Evening News (Sydney) of 1892-07-20.
-# https://www.staff.science.uu.nl/~gent0113/idl/idl.htm
+# https://webspace.science.uu.nl/~gent0113/idl/idl_alaska_samoa.htm
 
 # Although Shanks & Pottenger says they both switched to UT -11:30
 # in 1911, and to -11 in 1950. many earlier sources give -11
diff --git a/contrib/tzdata/checknow.awk b/contrib/tzdata/checknow.awk
index d722c03fd689..57ff3c02e789 100644
--- a/contrib/tzdata/checknow.awk
+++ b/contrib/tzdata/checknow.awk
@@ -45,7 +45,7 @@ END {
  for (zone in zone_data) {
     data = zone_data[zone]
     if (!zonenow[data]) {
-      printf "checknow.tab should have one of:%s\n", zones[data]
+      printf "zonenow.tab should have one of:%s\n", zones[data]
       zonenow[data] = zone # This suppresses duplicate diagnostics.
       status = 1
     }
diff --git a/contrib/tzdata/etcetera b/contrib/tzdata/etcetera
index 865a220c1f4b..29fbed9b9290 100644
--- a/contrib/tzdata/etcetera
+++ b/contrib/tzdata/etcetera
@@ -5,7 +5,7 @@
 
 # These entries are for uses not otherwise covered by the tz database.
 # Their main practical use is for platforms like Android that lack
-# support for POSIX-style TZ strings.  On such platforms these entries
+# support for POSIX.1-2017-style TZ strings.  On such platforms these entries
 # can be useful if the timezone database is wrong or if a ship or
 # aircraft at sea is not in a timezone.
 
diff --git a/contrib/tzdata/europe b/contrib/tzdata/europe
index 27f821e77600..c6b5270316b9 100644
--- a/contrib/tzdata/europe
+++ b/contrib/tzdata/europe
@@ -990,9 +990,34 @@ Zone	Europe/Sofia	1:33:16 -	LMT	1880
 # Czech Republic (Czechia)
 # Slovakia
 #
-# From Paul Eggert (2018-04-15):
-# The source for Czech data is: Kdy začíná a končí letní čas. 2018-04-15.
+# From Ivan Benovic (2024-01-30):
+# https://www.slov-lex.sk/pravne-predpisy/SK/ZZ/1946/54/
+# (This is an official link to the Czechoslovak Summer Time Act of
+# March 8, 1946 that authorizes the Czechoslovak government to set the
+# exact dates of change to summer time and back to Central European Time.
+# The act also implicitly confirms Central European Time as the
+# official time zone of Czechoslovakia and currently remains in force
+# in both the Czech Republic and Slovakia.)
+# https://www.psp.cz/eknih/1945pns/tisky/t0216_00.htm
+# (This is a link to the original legislative proposal dating back to
+# February 22, 1946. The accompanying memorandum to the proposal says
+# that an advisory committee on European railroad transportation that
+# met in Brussels in October 1945 decided that the change of time
+# should be carried out in all participating countries in a strictly
+# coordinated manner....)
+#
+# From Paul Eggert (2024-01-30):
+# The source for Czech data is: Kdy začíná a končí letní čas.
 # https://kalendar.beda.cz/kdy-zacina-a-konci-letni-cas
+# Its main text disagrees with its quoted sources only in 1918,
+# where the main text says spring and autumn transitions
+# occurred at 02:00 and 03:00 respectively (as usual),
+# whereas the 1918 source "Oznámení o zavedení letního času v roce 1918"
+# says transitions were at 01:00 and 02:00 respectively.
+# As the 1918 source appears to be a humorous piece, and it is
+# unlikely that Prague would have disagreed with its neighbors by an hour,
+# go with the main text for now.
+#
 # We know of no English-language name for historical Czech winter time;
 # abbreviate it as "GMT", as it happened to be GMT.
 #
diff --git a/contrib/tzdata/leap-seconds.list b/contrib/tzdata/leap-seconds.list
index 3fe9a1210e3c..e52effc257b2 100644
--- a/contrib/tzdata/leap-seconds.list
+++ b/contrib/tzdata/leap-seconds.list
@@ -1,255 +1,120 @@
+#	ATOMIC TIME.
+#	The Coordinated Universal Time (UTC) is the reference time scale derived
+#	from The "Temps Atomique International" (TAI) calculated by the Bureau
+#	International des Poids et Mesures (BIPM) using a worldwide network of atomic
+#	clocks. UTC differs from TAI by an integer number of seconds; it is the basis
+#	of all activities in the world.
 #
-#	In the following text, the symbol '#' introduces
-#	a comment, which continues from that symbol until
-#	the end of the line. A plain comment line has a
-#	whitespace character following the comment indicator.
-#	There are also special comment lines defined below.
-#	A special comment will always have a non-whitespace
-#	character in column 2.
-#
-#	A blank line should be ignored.
-#
-#	The following table shows the corrections that must
-#	be applied to compute International Atomic Time (TAI)
-#	from the Coordinated Universal Time (UTC) values that
-#	are transmitted by almost all time services.
-#
-#	The first column shows an epoch as a number of seconds
-#	since 1 January 1900, 00:00:00 (1900.0 is also used to
-#	indicate the same epoch.) Both of these time stamp formats
-#	ignore the complexities of the time scales that were
-#	used before the current definition of UTC at the start
-#	of 1972. (See note 3 below.)
-#	The second column shows the number of seconds that
-#	must be added to UTC to compute TAI for any timestamp
-#	at or after that epoch. The value on each line is
-#	valid from the indicated initial instant until the
-#	epoch given on the next one or indefinitely into the
-#	future if there is no next line.
-#	(The comment on each line shows the representation of
-#	the corresponding initial epoch in the usual
-#	day-month-year format. The epoch always begins at
-#	00:00:00 UTC on the indicated day. See Note 5 below.)
-#
-#	Important notes:
-#
-#	1. Coordinated Universal Time (UTC) is often referred to
-#	as Greenwich Mean Time (GMT). The GMT time scale is no
-#	longer used, and the use of GMT to designate UTC is
-#	discouraged.
-#
-#	2. The UTC time scale is realized by many national
-#	laboratories and timing centers. Each laboratory
-#	identifies its realization with its name: Thus
-#	UTC(NIST), UTC(USNO), etc. The differences among
-#	these different realizations are typically on the
-#	order of a few nanoseconds (i.e., 0.000 000 00x s)
-#	and can be ignored for many purposes. These differences
-#	are tabulated in Circular T, which is published monthly
-#	by the International Bureau of Weights and Measures
-#	(BIPM). See www.bipm.org for more information.
-#
-#	3. The current definition of the relationship between UTC
-#	and TAI dates from 1 January 1972. A number of different
-#	time scales were in use before that epoch, and it can be
-#	quite difficult to compute precise timestamps and time
-#	intervals in those "prehistoric" days. For more information,
-#	consult:
-#
-#		The Explanatory Supplement to the Astronomical
-#		Ephemeris.
-#	or
-#		Terry Quinn, "The BIPM and the Accurate Measurement
-#		of Time," Proc. of the IEEE, Vol. 79, pp. 894-905,
-#		July, 1991. <http://dx.doi.org/10.1109/5.84965>;
-#		reprinted in:
-#		   Christine Hackman and Donald B Sullivan (eds.)
-#		   Time and Frequency Measurement
-#		   American Association of Physics Teachers (1996)
-#		   <http://tf.nist.gov/general/pdf/1168.pdf>, pp. 75-86
-#
-#	4. The decision to insert a leap second into UTC is currently
-#	the responsibility of the International Earth Rotation and
-#	Reference Systems Service. (The name was changed from the
-#	International Earth Rotation Service, but the acronym IERS
-#	is still used.)
-#
-#	Leap seconds are announced by the IERS in its Bulletin C.
-#
-#	See www.iers.org for more details.
-#
-#	Every national laboratory and timing center uses the
-#	data from the BIPM and the IERS to construct UTC(lab),
-#	their local realization of UTC.
-#
-#	Although the definition also includes the possibility
-#	of dropping seconds ("negative" leap seconds), this has
-#	never been done and is unlikely to be necessary in the
-#	foreseeable future.
-#
-#	5. If your system keeps time as the number of seconds since
-#	some epoch (e.g., NTP timestamps), then the algorithm for
-#	assigning a UTC time stamp to an event that happens during a positive
-#	leap second is not well defined. The official name of that leap
-#	second is 23:59:60, but there is no way of representing that time
-#	in these systems.
-#	Many systems of this type effectively stop the system clock for
-#	one second during the leap second and use a time that is equivalent
-#	to 23:59:59 UTC twice. For these systems, the corresponding TAI
-#	timestamp would be obtained by advancing to the next entry in the
-#	following table when the time equivalent to 23:59:59 UTC
-#	is used for the second time. Thus the leap second which
-#	occurred on 30 June 1972 at 23:59:59 UTC would have TAI
-#	timestamps computed as follows:
-#
-#	...
-#	30 June 1972 23:59:59 (2287785599, first time):	TAI= UTC + 10 seconds
-#	30 June 1972 23:59:60 (2287785599,second time):	TAI= UTC + 11 seconds
-#	1  July 1972 00:00:00 (2287785600)		TAI= UTC + 11 seconds
-#	...
-#
-#	If your system realizes the leap second by repeating 00:00:00 UTC twice
-#	(this is possible but not usual), then the advance to the next entry
-#	in the table must occur the second time that a time equivalent to
-#	00:00:00 UTC is used. Thus, using the same example as above:
-#
-#	...
-#       30 June 1972 23:59:59 (2287785599):		TAI= UTC + 10 seconds
-#       30 June 1972 23:59:60 (2287785600, first time):	TAI= UTC + 10 seconds
-#       1  July 1972 00:00:00 (2287785600,second time):	TAI= UTC + 11 seconds
-#	...
-#
-#	in both cases the use of timestamps based on TAI produces a smooth
-#	time scale with no discontinuity in the time interval. However,
-#	although the long-term behavior of the time scale is correct in both
-#	methods, the second method is technically not correct because it adds
-#	the extra second to the wrong day.
-#
-#	This complexity would not be needed for negative leap seconds (if they
-#	are ever used). The UTC time would skip 23:59:59 and advance from
-#	23:59:58 to 00:00:00 in that case. The TAI offset would decrease by
-#	1 second at the same instant. This is a much easier situation to deal
-#	with, since the difficulty of unambiguously representing the epoch
-#	during the leap second does not arise.
-#
-#	Some systems implement leap seconds by amortizing the leap second
-#	over the last few minutes of the day. The frequency of the local
-#	clock is decreased (or increased) to realize the positive (or
-#	negative) leap second. This method removes the time step described
-#	above. Although the long-term behavior of the time scale is correct
-#	in this case, this method introduces an error during the adjustment
-#	period both in time and in frequency with respect to the official
-#	definition of UTC.
-#
-#	Questions or comments to:
-#		Judah Levine
-#		Time and Frequency Division
-#		NIST
-#		Boulder, Colorado
-#		Judah.Levine@nist.gov
-#
-#	Last Update of leap second values:   8 July 2016
-#
-#	The following line shows this last update date in NTP timestamp
-#	format. This is the date on which the most recent change to
-#	the leap second data was added to the file. This line can
-#	be identified by the unique pair of characters in the first two
-#	columns as shown below.
-#
-#$	 3676924800
-#
-#	The NTP timestamps are in units of seconds since the NTP epoch,
-#	which is 1 January 1900, 00:00:00. The Modified Julian Day number
-#	corresponding to the NTP time stamp, X, can be computed as
-#
-#	X/86400 + 15020
-#
-#	where the first term converts seconds to days and the second
-#	term adds the MJD corresponding to the time origin defined above.
-#	The integer portion of the result is the integer MJD for that
-#	day, and any remainder is the time of day, expressed as the
-#	fraction of the day since 0 hours UTC. The conversion from day
-#	fraction to seconds or to hours, minutes, and seconds may involve
-#	rounding or truncation, depending on the method used in the
-#	computation.
-#
-#	The data in this file will be updated periodically as new leap
-#	seconds are announced. In addition to being entered on the line
-#	above, the update time (in NTP format) will be added to the basic
-#	file name leap-seconds to form the name leap-seconds.<NTP TIME>.
-#	In addition, the generic name leap-seconds.list will always point to
-#	the most recent version of the file.
-#
-#	This update procedure will be performed only when a new leap second
-#	is announced.
-#
-#	The following entry specifies the expiration date of the data
-#	in this file in units of seconds since the origin at the instant
-#	1 January 1900, 00:00:00. This expiration date will be changed
-#	at least twice per year whether or not a new leap second is
-#	announced. These semi-annual changes will be made no later
-#	than 1 June and 1 December of each year to indicate what
-#	action (if any) is to be taken on 30 June and 31 December,
-#	respectively. (These are the customary effective dates for new
-#	leap seconds.) This expiration date will be identified by a
-#	unique pair of characters in columns 1 and 2 as shown below.
-#	In the unlikely event that a leap second is announced with an
-#	effective date other than 30 June or 31 December, then this
-#	file will be edited to include that leap second as soon as it is
-#	announced or at least one month before the effective date
-#	(whichever is later).
-#	If an announcement by the IERS specifies that no leap second is
-#	scheduled, then only the expiration date of the file will
-#	be advanced to show that the information in the file is still
-#	current -- the update time stamp, the data and the name of the file
-#	will not change.
-#
-#	Updated through IERS Bulletin C66
-#	File expires on:  28 June 2024
-#
-#@	3928521600
-#
-2272060800	10	# 1 Jan 1972
-2287785600	11	# 1 Jul 1972
-2303683200	12	# 1 Jan 1973
-2335219200	13	# 1 Jan 1974
-2366755200	14	# 1 Jan 1975
-2398291200	15	# 1 Jan 1976
-2429913600	16	# 1 Jan 1977
-2461449600	17	# 1 Jan 1978
-2492985600	18	# 1 Jan 1979
-2524521600	19	# 1 Jan 1980
-2571782400	20	# 1 Jul 1981
-2603318400	21	# 1 Jul 1982
-2634854400	22	# 1 Jul 1983
-2698012800	23	# 1 Jul 1985
-2776982400	24	# 1 Jan 1988
-2840140800	25	# 1 Jan 1990
-2871676800	26	# 1 Jan 1991
-2918937600	27	# 1 Jul 1992
-2950473600	28	# 1 Jul 1993
-2982009600	29	# 1 Jul 1994
-3029443200	30	# 1 Jan 1996
-3076704000	31	# 1 Jul 1997
-3124137600	32	# 1 Jan 1999
-3345062400	33	# 1 Jan 2006
-3439756800	34	# 1 Jan 2009
-3550089600	35	# 1 Jul 2012
-3644697600	36	# 1 Jul 2015
-3692217600	37	# 1 Jan 2017
-#
-#	the following special comment contains the
-#	hash value of the data in this file computed
-#	use the secure hash algorithm as specified
-#	by FIPS 180-1. See the files in ~/pub/sha for
-#	the details of how this hash value is
-#	computed. Note that the hash computation
-#	ignores comments and whitespace characters
-#	in data lines. It includes the NTP values
-#	of both the last modification time and the
-#	expiration time of the file, but not the
-#	white space on those lines.
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