There are some cases where core Envoy code (or tests) depends on extensions. One example:

//source/extensions/access_loggers/grpc:http_config
//source/extensions/access_loggers/grpc:tcp_config

are used by:

//test/integration/http2_upstream_integration_test
//test/common/access_log/access_log_impl_test

This poses an issue for users like Google, who import only specific whitelisted extensions. We have to disable tests that depend on non-whitelisted extensions. I think we'd like to add some logic to check_format or similar, to catch these dependencies before they're introduced.

Not sure if this is related to #7903, likely seems related to #2910.