1 files changed, 14 insertions, 13 deletions
diff --git a/contrib/tzdata/etcetera b/contrib/tzdata/etcetera
index 987a6483b644..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.
 
@@ -16,22 +16,23 @@
 # Do not use a POSIX TZ setting like TZ='GMT+4', which is four hours
 # behind GMT but uses the completely misleading abbreviation "GMT".
 
-Zone	Etc/GMT		0	-	GMT
+# The following zone is used by tzcode functions like gmtime,
+# which load the "UTC" file to handle seconds properly.
 Zone	Etc/UTC		0	-	UTC
 
+# Functions like gmtime load the "GMT" file to handle leap seconds properly.
+# Vanguard section, which works with most .zi parsers.
+#Zone	GMT		0	-	GMT
+# Rearguard section, for TZUpdater 2.3.2 and earlier.
+Zone	Etc/GMT		0	-	GMT
+
 # The following link uses older naming conventions,
 # but it belongs here, not in the file 'backward',
-# as functions like gmtime load the "UTC" file to handle leap seconds properly.
-# We want this to work even on installations that omit the other older names.
-Link	Etc/UTC				UTC
-
-Link	Etc/UTC				Etc/Universal
-Link	Etc/UTC				Etc/Zulu
-
-Link	Etc/GMT				Etc/Greenwich
-Link	Etc/GMT				Etc/GMT-0
-Link	Etc/GMT				Etc/GMT+0
-Link	Etc/GMT				Etc/GMT0
+# as it is needed for tzcode releases through 2022a,
+# where functions like gmtime load "GMT" instead of the "Etc/UTC".
+# We want this to work even on installations that omit 'backward'.
+Link	Etc/GMT				GMT
+# End of rearguard section.
 
 # Be consistent with POSIX TZ settings in the Zone names,
 # even though this is the opposite of what many people expect.