$ git clone -n https://src.fedoraproject.org/rpms/nitrogen.git /var/lib/mock/f39-build-1592084-38306/root/chroot_tmpdir/scmroot/nitrogen
Cloning into '/var/lib/mock/f39-build-1592084-38306/root/chroot_tmpdir/scmroot/nitrogen'...
$ git fetch origin 8ac6e4095219e70bc40bd874547bd49ff5df5a70:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/nitrogen
 * [new ref]         8ac6e4095219e70bc40bd874547bd49ff5df5a70 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8ac6e40 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild