$ git clone -n https://src.fedoraproject.org/rpms/rust-gst-plugin-mp4 /var/lib/mock/f42-build-3428999-45391/root/chroot_tmpdir/scmroot/rust-gst-plugin-mp4
Cloning into '/var/lib/mock/f42-build-3428999-45391/root/chroot_tmpdir/scmroot/rust-gst-plugin-mp4'...
$ git fetch origin ad6555709398e53ff06d9d8de9e823d5626d884e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gst-plugin-mp4
 * [new ref]         ad6555709398e53ff06d9d8de9e823d5626d884e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ad65557 Update to 0.13.5 (rhbz#2349775)