$ git clone -n https://src.fedoraproject.org/rpms/gstreamer1-plugins-ugly-free.git /var/lib/mock/f39-build-2079993-49693/root/chroot_tmpdir/scmroot/gstreamer1-plugins-ugly-free
Cloning into '/var/lib/mock/f39-build-2079993-49693/root/chroot_tmpdir/scmroot/gstreamer1-plugins-ugly-free'...
$ git fetch origin de612f096a5531ad16e1621b54940134a89ed2e3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gstreamer1-plugins-ugly-free
 * [new ref]         de612f096a5531ad16e1621b54940134a89ed2e3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at de612f0 1.22.8