11.2 contains man pages for pcap-filter and pcap-linktype in man7. Those are missing in 10.2-RELEASE. The other pcap man pages in man3 are present. The man page for pcap-filter contains the only description of the filters used by tcpdump.
sermons# uname -a
FreeBSD sermons 11.2-RELEASE-p8 FreeBSD 11.2-RELEASE-p8 #0: Tue Jan 8 21:35:12 UTC 2019 firstname.lastname@example.org:/usr/obj/usr/src/sys/GENERIC amd64
sermons# ll /usr/share/man/man7/pcap*
-r--r--r-- 1 root wheel 9706 Oct 10 2016 pcap-filter.7.gz
-r--r--r-- 1 root wheel 1166 Oct 10 2016 pcap-linktype.7.gz
master% uname -a
FreeBSD master 12.0-RELEASE-p3 FreeBSD 12.0-RELEASE-p3 GENERIC amd64
master% ll /usr/share/man/man7/pcap*
ls: No match.
Should have included that master was running 11.2 before and then it was upgraded to 12.0-RELEASE using freebsd-update. Master does not contain /usr/src, but sermons does if that makes any difference.
This is a duplicate of https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=237893 - or rather it is a duplicate of this one but the other one has a patch now.
Obsoleted by PR 237893.