$ git clone -n https://src.fedoraproject.org/rpms/arpwatch.git /var/lib/mock/f39-build-1927948-43062/root/chroot_tmpdir/scmroot/arpwatch
Cloning into '/var/lib/mock/f39-build-1927948-43062/root/chroot_tmpdir/scmroot/arpwatch'...
$ git fetch origin dc790c3128d1ab8216f22b9931457d37ad7c451d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/arpwatch
 * [new ref]         dc790c3128d1ab8216f22b9931457d37ad7c451d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dc790c3 Switch to dynamically-allocated service user/group ID’s