$ git clone -n https://src.fedoraproject.org/rpms/wsjtx.git /var/lib/mock/f40-build-780892-131370/root/chroot_tmpdir/scmroot/wsjtx
Cloning into '/var/lib/mock/f40-build-780892-131370/root/chroot_tmpdir/scmroot/wsjtx'...
$ git fetch origin 733f9caaed35a6879ce94b3aaf1660a77b5c1a88:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/wsjtx
 * [new ref]         733f9caaed35a6879ce94b3aaf1660a77b5c1a88 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 733f9ca Upload sources.