$ git clone -n https://src.fedoraproject.org/rpms/gtk3.git /var/lib/mock/f39-build-1533379-36227/root/chroot_tmpdir/scmroot/gtk3
Cloning into '/var/lib/mock/f39-build-1533379-36227/root/chroot_tmpdir/scmroot/gtk3'...
$ git fetch origin 4ba85a1e273b3a64c9e26c0ee55c79b20952cf21:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gtk3
 * [new ref]         4ba85a1e273b3a64c9e26c0ee55c79b20952cf21 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4ba85a1 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild