$ git clone -n https://src.fedoraproject.org/rpms/cxxtools.git /var/lib/mock/f40-build-790287-136404/root/chroot_tmpdir/scmroot/cxxtools
Cloning into '/var/lib/mock/f40-build-790287-136404/root/chroot_tmpdir/scmroot/cxxtools'...
$ git fetch origin 890fd4e972165370b698bb2c1d5d39f51984a572:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cxxtools
 * [new ref]         890fd4e972165370b698bb2c1d5d39f51984a572 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 890fd4e Rebuilt disable test suite