pcap_major_version(3) on FreeBSD
The text e0d0fc9f9ee1, as FreeBSD 10.4-RELEASE, FreeBSD 10.3-RELEASE, FreeBSD 10.2-RELEASE, FreeBSD 10.1-RELEASE, FreeBSD 10.0-RELEASE, FreeBSD 9.3-RELEASE, FreeBSD 9.2-RELEASE, FreeBSD 9.1-RELEASE shipped it.
get the version number of a savefile