$ git clone -n https://src.fedoraproject.org/rpms/R-markdown.git /var/lib/mock/f38-build-724223-99404/root/chroot_tmpdir/scmroot/R-markdown
Cloning into '/var/lib/mock/f38-build-724223-99404/root/chroot_tmpdir/scmroot/R-markdown'...
$ git fetch origin cc00b6711b72839aa0cee7626c2d68e28c72320b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-markdown
 * [new ref]         cc00b6711b72839aa0cee7626c2d68e28c72320b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cc00b67 R-maint-sig mass rebuild