$ git clone -n https://src.fedoraproject.org/rpms/bookworm.git /var/lib/mock/f39-build-1456186-32921/root/chroot_tmpdir/scmroot/bookworm
Cloning into '/var/lib/mock/f39-build-1456186-32921/root/chroot_tmpdir/scmroot/bookworm'...
$ git fetch origin 839e6a2bef4895fdb9a62ca402d22b80ce6edfa5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/bookworm
 * [new ref]         839e6a2bef4895fdb9a62ca402d22b80ce6edfa5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 839e6a2 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild