$ git clone -n https://src.fedoraproject.org/rpms/gstreamer1.git /var/lib/mock/f45-build-39669-750/root/chroot_tmpdir/scmroot/gstreamer1
Cloning into '/var/lib/mock/f45-build-39669-750/root/chroot_tmpdir/scmroot/gstreamer1'...
$ git fetch origin 9739bea5fcdf29c6fbce027018c7b120ee962209:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gstreamer1
 * [new ref]         9739bea5fcdf29c6fbce027018c7b120ee962209 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9739bea 1.28.7