$ git clone -n https://src.fedoraproject.org/rpms/containers-common.git /var/lib/mock/f39-build-1510803-35511/root/chroot_tmpdir/scmroot/containers-common
Cloning into '/var/lib/mock/f39-build-1510803-35511/root/chroot_tmpdir/scmroot/containers-common'...
$ git fetch origin 25f52527948d1c85117d090f9b5a608c1752cc6c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/containers-common
 * [new ref]         25f52527948d1c85117d090f9b5a608c1752cc6c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 25f5252 local build