$ git clone -n https://src.fedoraproject.org/rpms/elementary-onboarding.git /var/lib/mock/f39-build-1560145-37332/root/chroot_tmpdir/scmroot/elementary-onboarding
Cloning into '/var/lib/mock/f39-build-1560145-37332/root/chroot_tmpdir/scmroot/elementary-onboarding'...
$ git fetch origin 8cb8140bd570768dac30f6a9b2571e19a2b36aa9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/elementary-onboarding
 * [new ref]         8cb8140bd570768dac30f6a9b2571e19a2b36aa9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8cb8140 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild