$ git clone -n https://src.fedoraproject.org/rpms/gamescope.git /var/lib/mock/f40-build-2430272-60608/root/chroot_tmpdir/scmroot/gamescope
Cloning into '/var/lib/mock/f40-build-2430272-60608/root/chroot_tmpdir/scmroot/gamescope'...
$ git fetch origin 83fb659838965adeb0c923cfad137df2383e2559:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gamescope
 * [new ref]         83fb659838965adeb0c923cfad137df2383e2559 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 83fb659 Rebase to 3.14.1