$ git clone -n https://src.fedoraproject.org/rpms/supertux.git /var/lib/mock/f41-build-side-1-2771377-32225/root/chroot_tmpdir/scmroot/supertux
Cloning into '/var/lib/mock/f41-build-side-1-2771377-32225/root/chroot_tmpdir/scmroot/supertux'...
$ git fetch origin a78f76ce7975d4c7711c3c246eeea8200cc15a64:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/supertux
 * [new ref]         a78f76ce7975d4c7711c3c246eeea8200cc15a64 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a78f76c convert GPLv2+ license to SPDX