$ git clone -n https://src.fedoraproject.org/rpms/c4fs.git /var/lib/mock/f39-build-1509529-35443/root/chroot_tmpdir/scmroot/c4fs
Cloning into '/var/lib/mock/f39-build-1509529-35443/root/chroot_tmpdir/scmroot/c4fs'...
$ git fetch origin cf28b4513640a9ca4ead79f2557e0f8b9cb6e3c3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/c4fs
 * [new ref]         cf28b4513640a9ca4ead79f2557e0f8b9cb6e3c3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cf28b45 Fix wrong multilib library paths in .cmake files (fix RHBZ#2223194)