$ git clone -n https://src.fedoraproject.org/rpms/rust-gstreamer-gl-sys /var/lib/mock/f42-build-3429018-45391/root/chroot_tmpdir/scmroot/rust-gstreamer-gl-sys
Cloning into '/var/lib/mock/f42-build-3429018-45391/root/chroot_tmpdir/scmroot/rust-gstreamer-gl-sys'...
$ git fetch origin 51bce950270e565e6290ed7e87a0c32f4a4641fa:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gstreamer-gl-sys
 * [new ref]         51bce950270e565e6290ed7e87a0c32f4a4641fa -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 51bce95 Update to version 0.23.5; Fixes RHBZ#2333670