sync(8) on FreeBSD
The text 1487f0836d72, as FreeBSD 14.5-RELEASE, FreeBSD 14.4-RELEASE, FreeBSD 14.3-RELEASE, FreeBSD 14.2-RELEASE, FreeBSD 14.1-RELEASE, FreeBSD 13.5-RELEASE, FreeBSD 13.4-RELEASE shipped it.
force completion of pending disk writes (flush cache)