This directory previously contained Go modules not packaged in Debian
(bazelbuild/reclient, bazelbuild/remote-apis-sdks, protoc-gen-bq-schema).

As of upstream v1.5.19, siso no longer imports any of these modules
(reproxy integration was dropped), so no vendored dependencies remain.

The directory is kept as a placeholder in case future upstream releases
reintroduce dependencies not available in Debian.
