$ git clone -n https://src.fedoraproject.org/rpms/fgrun.git /var/lib/mock/f42-build-side-1-3586545-46923/root/chroot_tmpdir/scmroot/fgrun
Cloning into '/var/lib/mock/f42-build-side-1-3586545-46923/root/chroot_tmpdir/scmroot/fgrun'...
$ git fetch origin 94a96a9ff76fd551f40b7d9068c53574c3b498d1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fgrun
 * [new ref]         94a96a9ff76fd551f40b7d9068c53574c3b498d1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 94a96a9 rebuild with newer SimGear