$ git clone -n https://src.fedoraproject.org/rpms/gtk+extra.git /var/lib/mock/f41-build-836256-158795/root/chroot_tmpdir/scmroot/gtk+extra
Cloning into '/var/lib/mock/f41-build-836256-158795/root/chroot_tmpdir/scmroot/gtk+extra'...
$ git fetch origin 302965fe0ee4990b22ba6d32701719abf2835abb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gtk+extra
 * [new ref]         302965fe0ee4990b22ba6d32701719abf2835abb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 302965f fix fatal specfile error