Even though US-ASCII (= ANSI X3.4-1986) only defines 128 characters,

the POSIX standard explicitly requires in section 6.2 that "the POSIX
locale shall contain 256 single-byte characters", see:
https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap06.html#tag_06_02

So the current behaviour of treating non-ASCII bytes in an LC_CTYPE=POSIX
input stream as if they were characters is not a POSIX violation, but
actually required by the standard - and not just for awk(1), but for
utility programs in general and even for library functions in general.
Consequently, delete the wrong sentence i added to the STANDARDS section
last year.

Thanks to millert@ and jmc@ for making me realize my mistake.
OK millert@ jmc@

usr.bin/awk/awk.1

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: awk.1,v 1.69 2024/07/30 13:55:11 jmc Exp $
+.\"	$OpenBSD: awk.1,v 1.70 2024/08/11 18:24:43 schwarze Exp $
 .\"
 .\" Copyright (C) Lucent Technologies 1997
 .\" All Rights Reserved
@@ -22,7 +22,7 @@
 .\" ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 .\" THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: July 30 2024 $
+.Dd $Mdocdate: August 11 2024 $
 .Dt AWK 1
 .Os
 .Sh NAME
@@ -1041,11 +1041,6 @@ and
 .Fn srand
 has been changed to support non-deterministic random numbers.
 .Pp
-In
-.Ev LC_CTYPE Ns Li =POSIX
-mode, treating non-ASCII input bytes as non-letter characters rather
-than as input encoding errors intentionally violates the specification.
-.Pp
 The flags
 .Op Fl \&dV ,
 .Op Fl -csv ,