These two IPv6 netmasks do not appear to be used anywhere anymore.

Index: sys/netinet6/in6.c
===================================================================
RCS file: /OpenBSD/src/sys/netinet6/in6.c,v
diff -u -p -u -p -r1.279 in6.c
--- sys/netinet6/in6.c	22 Mar 2026 23:14:00 -0000	1.279
+++ sys/netinet6/in6.c	20 Sep 2026 16:47:44 -0000
@@ -107,10 +107,8 @@ const struct in6_addr in6addr_linklocal_
 const struct in6_addr in6addr_linklocal_allrouters =
 	IN6ADDR_LINKLOCAL_ALLROUTERS_INIT;
 
-const struct in6_addr in6mask0 = IN6MASK0;
 const struct in6_addr in6mask32 = IN6MASK32;
 const struct in6_addr in6mask64 = IN6MASK64;
-const struct in6_addr in6mask96 = IN6MASK96;
 const struct in6_addr in6mask128 = IN6MASK128;
 
 int in6_ioctl(u_long, caddr_t, struct ifnet *, int);
Index: sys/netinet6/in6.h
===================================================================
RCS file: /OpenBSD/src/sys/netinet6/in6.h,v
diff -u -p -u -p -r1.125 in6.h
--- sys/netinet6/in6.h	16 Sep 2025 09:19:16 -0000	1.125
+++ sys/netinet6/in6.h	20 Sep 2026 16:47:44 -0000
@@ -117,22 +117,17 @@ struct sockaddr_in6 {
  * Local definition for masks
  */
 #ifdef _KERNEL	/* XXX nonstandard */
-#define IN6MASK0	{{{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }}}
 #define IN6MASK32	{{{ 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, \
 			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }}}
 #define IN6MASK64	{{{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, \
 			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }}}
-#define IN6MASK96	{{{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, \
-			    0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 }}}
 #define IN6MASK128	{{{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, \
 			    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }}}
 
 extern const struct sockaddr_in6 sa6_any;
 
-extern const struct in6_addr in6mask0;
 extern const struct in6_addr in6mask32;
 extern const struct in6_addr in6mask64;
-extern const struct in6_addr in6mask96;
 extern const struct in6_addr in6mask128;
 #endif /* _KERNEL */