$ git clone -n https://src.fedoraproject.org/rpms/glibd.git /var/lib/mock/f40-build-789764-135976/root/chroot_tmpdir/scmroot/glibd
Cloning into '/var/lib/mock/f40-build-789764-135976/root/chroot_tmpdir/scmroot/glibd'...
$ git fetch origin fa2fe421eb3f0512b506f50239998e329a10aadb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/glibd
 * [new ref]         fa2fe421eb3f0512b506f50239998e329a10aadb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fa2fe42 Rebase to 2.4.3