$ git clone -n https://src.fedoraproject.org/rpms/ocaml-base64.git /var/lib/mock/f42-build-865914-173583/root/chroot_tmpdir/scmroot/ocaml-base64
Cloning into '/var/lib/mock/f42-build-865914-173583/root/chroot_tmpdir/scmroot/ocaml-base64'...
$ git fetch origin fb216a8a4502c5ccdfd65c854514eaa01105182c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ocaml-base64
 * [new ref]         fb216a8a4502c5ccdfd65c854514eaa01105182c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fb216a8 OCaml 5.3.0 rebuild for Fedora 42