$ git clone -n https://src.fedoraproject.org/rpms/python-gstreamer1.git /var/lib/mock/f42-build-side-1-3589340-46957/root/chroot_tmpdir/scmroot/python-gstreamer1
Cloning into '/var/lib/mock/f42-build-side-1-3589340-46957/root/chroot_tmpdir/scmroot/python-gstreamer1'...
$ git fetch origin b975d4911ca5609c04a5f148bdc79fc69b30c11b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-gstreamer1
 * [new ref]         b975d4911ca5609c04a5f148bdc79fc69b30c11b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b975d49 1.26.3