$ git clone -n https://src.fedoraproject.org/rpms/katomic.git /var/lib/mock/f40-build-2111436-50662/root/chroot_tmpdir/scmroot/katomic
Cloning into '/var/lib/mock/f40-build-2111436-50662/root/chroot_tmpdir/scmroot/katomic'...
$ git fetch origin 12466dbcfdc21aeee92efde727e24801444cccd6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/katomic
 * [new ref]         12466dbcfdc21aeee92efde727e24801444cccd6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 12466db Update sources file