- unbound.conf manpage: explicitly mention RFC6891.

doc/Changelog

@@ -13,6 +13,7 @@
 	- TTL change: TTL decoding was updated to adhere to RFC8767 section 4
 	  where a 'set high-order bit' means the value is positive instead of
 	  0.
+	- unbound.conf manpage: explicitly mention RFC6891.
 
 18 September 2025: Wouter
 	- Tag for 1.24.0 release. Includes the fixes below after rc1.

doc/unbound.conf.5.in

@@ -1969,7 +1969,7 @@ Default:  \(dq3 2 1 0 0\(dq
 .B harden\-short\-bufsize: \fI<yes or no>\fP 
 Very small EDNS buffer sizes from queries are ignored.
 .sp
-Default: yes (as described in the standard)
+Default: yes (per \fI\%RFC 6891\fP)
 .UNINDENT
 .INDENT 0.0
 .TP
@@ -2600,6 +2600,12 @@ If
 \fI\%serve\-expired\-client\-timeout\fP
 is also used then it is RECOMMENDED to use 30 as the value (\fI\%RFC 8767\fP).
 .sp
+This value is capped by the original TTL of the record.
+This means that records with higher original TTL than this value will use
+this value for expired replies.
+Records with lower original TTL than this value will use their original TTL
+for expired replies.
+.sp
 Default: 30
 .UNINDENT
 .INDENT 0.0

doc/unbound.conf.rst

@@ -1744,7 +1744,7 @@ These options are part of the **server:** clause.
 @@UAHL@unbound.conf@harden-short-bufsize@@: *<yes or no>*
     Very small EDNS buffer sizes from queries are ignored.
 
-    Default: yes (as described in the standard)
+    Default: yes (per :rfc:`6891`)
 
 
 @@UAHL@unbound.conf@harden-large-queries@@: *<yes or no>*