diff --git a/Makeconfig b/Makeconfig
index d0108d2caa..a4be5b0e21 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -285,19 +285,17 @@ ifndef leapseconds
 leapseconds = /dev/null
 endif
 
-# What timezone's DST rules should be used when a POSIX-style TZ
-# environment variable doesn't specify any rules.  For 1003.1 compliance
-# this timezone must use rules that are as U.S. federal law defines DST.
-# Run `make -C time echo-zonenames' to see a list of available zone names.
-# This setting can be changed with `zic -p TIMEZONE' at any time.
-# If you want POSIX.1 compatibility, use `America/New_York'.
+# What timezone's DST rules to use when testing that glibc does
+# not mishandle TZif files built with zic's obsolescent -p option.
+# This macro no longer affects glibc's code or installation.
 ifndef posixrules
 posixrules = America/New_York
 endif
 
-# Where to install the "posixrules" timezone file; this is file
-# whose contents $(posixrules) specifies.  If this is a relative
-# pathname, it is relative to $(zonedir).
+# Where to put the "posixrules" timezone file used during testing; this
+# is the file whose contents $(posixrules) specifies.
+# If this is a relative pathname, it is relative to $(zonedir).
+# Like posixrules, this macro no longer affects glibc's code or installation.
 ifndef posixrules-file
 posixrules-file = posixrules
 endif
diff --git a/NEWS b/NEWS
index 3e6227a448..a62fb8136d 100644
--- a/NEWS
+++ b/NEWS
@@ -84,12 +84,11 @@ Deprecated and removed features, and other changes affecting compatibility:
   explicitly because of the executable bit in GNU_STACK, and the stack is
   not already executable.  Instead, loading such objects will fail.
 
-* The default daylight saving rules for old Unix System V style TZ
-  strings like TZ="AST4ADT" are now those of current US DST.  Although
-  the rules were supposed to be those of /usr/share/zoneinfo/posixrules,
-  this feature, which has been disabled by default and marked obsolete
-  upstream in tzcode, did not work in either glibc or tzcode, and in
-  practice posixrules invariably specified current US DST anyway.
+* The US daylight saving rule is now the default for incomplete TZ
+  strings like TZ="AST4ADT" that use the TZ syntax from circa-1980s
+  Unix System V.  Formerly the rule was documented to be that of
+  /usr/share/zoneinfo/posixrules but this did not work and in practice
+  posixrules invariably specified the US rule anyway.
 
 Changes to build and runtime requirements:
 
diff --git a/manual/time.texi b/manual/time.texi
index 28d8912446..cff94cb48b 100644
--- a/manual/time.texi
+++ b/manual/time.texi
@@ -2759,11 +2759,9 @@ and offset for the corresponding daylight saving time zone; if the
 
 The remainder of the proleptic format, which starts with the first comma,
 describes when daylight saving time is in effect.  This remainder is
-optional and if omitted, @theglibc{} defaults to US daylight saving rules.
-rules that would be used if @env{TZ} had the value @t{"posixrules"}.
-However, other POSIX implementations default to different daylight
-saving rules, so portable @env{TZ} settings should not omit the
-remainder.
+optional and if omitted, @theglibc{} defaults to the US daylight saving rule.
+POSIX does not specify this default, so portable @env{TZ} settings
+should not omit the remainder.
 
 In the remainder, the @var{start} field is when daylight saving time goes into
 effect and the @var{end} field is when the change is made back to standard