$ git clone -n https://src.fedoraproject.org/rpms/R-RInside /var/lib/mock/f39-build-1586679-38208/root/chroot_tmpdir/scmroot/R-RInside
Cloning into '/var/lib/mock/f39-build-1586679-38208/root/chroot_tmpdir/scmroot/R-RInside'...
$ git fetch origin cfca6de684d260c760108c0dd8c501b648789c81:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-RInside
 * [new ref]         cfca6de684d260c760108c0dd8c501b648789c81 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cfca6de Fix build requires