hexdump(3) on FreeBSD
The text 9fff5b22c39f, as FreeBSD 14.3-RELEASE, FreeBSD 14.2-RELEASE, FreeBSD 14.1-RELEASE, FreeBSD 14.0-RELEASE, FreeBSD 13.5-RELEASE, FreeBSD 13.4-RELEASE, FreeBSD 13.3-RELEASE shipped it.
dump a block of bytes to standard out in hexadecimal form