$ git clone -n https://src.fedoraproject.org/rpms/ocaml-jsonm.git /var/lib/mock/f42-build-865651-173376/root/chroot_tmpdir/scmroot/ocaml-jsonm
Cloning into '/var/lib/mock/f42-build-865651-173376/root/chroot_tmpdir/scmroot/ocaml-jsonm'...
$ git fetch origin 8666200476fa7c84cf12eca86e6f577ad9865da9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-jsonm
 * [new ref]         8666200476fa7c84cf12eca86e6f577ad9865da9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8666200 OCaml 5.3.0 rebuild for Fedora 42