+- When a man(1) command returns no result and there was an -S
+ argument, check the -S argument against the list of valid
+ architectures and say "Unknown architecture AAA" rather than
+ "No entry for NNN in the manual" if there is no match.
+ Requires moving the lists of valid architectures out of
+ mdoc_validate.c such that they can be used by main.c.
+ Discussed with jmc@ 10 Aug 2018 19:20:12 +0100.
+ loc ** exist * algo * size * imp **
+
+- warn about duplicate .Sh/.Ss heads
+ gre(4): Rename duplicate sections 20 Apr 2018 15:27:33 +0200
+ loc * exist * algo * size * imp **
+
+- style message about macros inside .Bd -literal and .Dl, in particular
+ font changing macros like .Cm, .Ar, .Fa (from the mdoclint TODO)
+
+- style message about mismatches between the section number in the
+ file name (if it is known) and the section number in .Dt
+ (from the mdoclint TODO)
+
+- style message about NULL without .Dv (from the mdoclint TODO)
+
+- style message about error constants without .Er (from the mdoclint TODO)
+