$ git clone -n https://src.fedoraproject.org/rpms/caribou.git /var/lib/mock/f39-build-1517918-35784/root/chroot_tmpdir/scmroot/caribou
Cloning into '/var/lib/mock/f39-build-1517918-35784/root/chroot_tmpdir/scmroot/caribou'...
$ git fetch origin 6ab61e074684d823ffe0ac995b65c7b1a53888f7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/caribou
 * [new ref]         6ab61e074684d823ffe0ac995b65c7b1a53888f7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6ab61e0 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild