$ git clone -n https://src.fedoraproject.org/rpms/rear.git /var/lib/mock/f41-build-854739-166952/root/chroot_tmpdir/scmroot/rear
Cloning into '/var/lib/mock/f41-build-854739-166952/root/chroot_tmpdir/scmroot/rear'...
$ git fetch origin 63d4184b65a79e399193921c1dd96a9f4664409e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rear
 * [new ref]         63d4184b65a79e399193921c1dd96a9f4664409e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 63d4184 Bump Release, update %changelog