$ git clone -n https://src.fedoraproject.org/rpms/gstreamer1-plugin-libav.git /var/lib/mock/f41-build-808262-145751/root/chroot_tmpdir/scmroot/gstreamer1-plugin-libav
Cloning into '/var/lib/mock/f41-build-808262-145751/root/chroot_tmpdir/scmroot/gstreamer1-plugin-libav'...
$ git fetch origin 5f40c971d03eb966fc3b3f0e6c5f9fea09f4dec9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gstreamer1-plugin-libav
 * [new ref]         5f40c971d03eb966fc3b3f0e6c5f9fea09f4dec9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f40c97 1.24.3