pcap_is_swapped(3) on FreeBSD
The text b4a9a38848d8, 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, FreeBSD 9.0-RELEASE shipped it.
find out whether a savefile has the native byte order