$ git clone -n https://src.fedoraproject.org/rpms/gstreamer1-plugins-base.git /var/lib/mock/f41-build-861153-169418/root/chroot_tmpdir/scmroot/gstreamer1-plugins-base
Cloning into '/var/lib/mock/f41-build-861153-169418/root/chroot_tmpdir/scmroot/gstreamer1-plugins-base'...
$ git fetch origin 32bfe196430dc6840a5b0a1f87ef06e86765770a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gstreamer1-plugins-base
 * [new ref]         32bfe196430dc6840a5b0a1f87ef06e86765770a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 32bfe19 sources