These two routines do not appear to be used anywhere.

Index: sys/isofs/cd9660/cd9660_node.h
===================================================================
RCS file: /OpenBSD/src/sys/isofs/cd9660/cd9660_node.h,v
diff -u -p -u -p -r1.23 cd9660_node.h
--- sys/isofs/cd9660/cd9660_node.h	13 May 2024 01:15:53 -0000	1.23
+++ sys/isofs/cd9660/cd9660_node.h	20 Sep 2026 16:47:44 -0000
@@ -99,8 +99,6 @@ int	cd9660_getattr(void *);
 int	cd9660_setattr(void *);
 int	cd9660_read(void *);
 int	cd9660_ioctl(void *);
-int	cd9660_mmap(void *);
-int	cd9660_seek(void *);
 int	cd9660_readdir(void *);
 int	cd9660_readlink(void *);
 int	cd9660_inactive(void *);
Index: sys/isofs/cd9660/cd9660_vnops.c
===================================================================
RCS file: /OpenBSD/src/sys/isofs/cd9660/cd9660_vnops.c,v
diff -u -p -u -p -r1.97 cd9660_vnops.c
--- sys/isofs/cd9660/cd9660_vnops.c	18 Oct 2024 05:52:32 -0000	1.97
+++ sys/isofs/cd9660/cd9660_vnops.c	20 Sep 2026 16:47:44 -0000
@@ -286,29 +286,6 @@ cd9660_ioctl(void *v)
 	return (ENOTTY);
 }
 
-/*
- * Mmap a file
- *
- * NB Currently unsupported.
- */
-int
-cd9660_mmap(void *v)
-{
-
-	return (EINVAL);
-}
-
-/*
- * Seek on a file
- *
- * Nothing to do, so just return.
- */
-int
-cd9660_seek(void *v)
-{
-	return (0);
-}
-
 int
 iso_uiodir(struct isoreaddir *idp, struct dirent *dp, off_t off)
 {