$ git clone -n https://src.fedoraproject.org/rpms/gnome-shell-extension-gamerzilla.git /var/lib/mock/f42-build-side-1-3536443-46558/root/chroot_tmpdir/scmroot/gnome-shell-extension-gamerzilla
Cloning into '/var/lib/mock/f42-build-side-1-3536443-46558/root/chroot_tmpdir/scmroot/gnome-shell-extension-gamerzilla'...
$ git fetch origin d10e7aeedafa0462dfa48575e18d0885cfeaf9c1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-shell-extension-gamerzilla
 * [new ref]         d10e7aeedafa0462dfa48575e18d0885cfeaf9c1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d10e7ae Update to new release.