$ git clone -n https://src.fedoraproject.org/rpms/R-rjson.git /var/lib/mock/f39-build-1536187-36265/root/chroot_tmpdir/scmroot/R-rjson
Cloning into '/var/lib/mock/f39-build-1536187-36265/root/chroot_tmpdir/scmroot/R-rjson'...
$ git fetch origin e47dd518202a1603c3b3bf606349ef5999820081:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rjson
 * [new ref]         e47dd518202a1603c3b3bf606349ef5999820081 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e47dd51 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild