$ git clone -n https://src.fedoraproject.org/rpms/cjs.git /var/lib/mock/f45-build-6731-350/root/chroot_tmpdir/scmroot/cjs
Cloning into '/var/lib/mock/f45-build-6731-350/root/chroot_tmpdir/scmroot/cjs'...
$ git fetch origin 9c8c939729123ab67524ca16bb432d235e9867e0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cjs
 * [new ref]         9c8c939729123ab67524ca16bb432d235e9867e0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9c8c939 Switch to rpmautospec and new rpm meson support