$ git clone -n https://src.fedoraproject.org/rpms/gstreamer1-plugin-libav.git /var/lib/mock/f45-build-13112-446/root/chroot_tmpdir/scmroot/gstreamer1-plugin-libav
Cloning into '/var/lib/mock/f45-build-13112-446/root/chroot_tmpdir/scmroot/gstreamer1-plugin-libav'...
$ git fetch origin d7b2d4dabef49d380ecb4790ecc6d4fd8f49e55b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gstreamer1-plugin-libav
 * [new ref]         d7b2d4dabef49d380ecb4790ecc6d4fd8f49e55b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d7b2d4d 1.28.6