For now only the discussion blocks were supported. If we had a custom XBlock that specified `completion_mode = XBlockCompletionMode.EXCLUDED`, then it could never be marked as completed on the course outline page, despite being marked as such inside the learning sequence.
Open EdX Features ----------------- This is the root package for Open edX features that extend the edX platform. The intention is that these features would ideally live in an external repository, but for now they live in edx-platform but are cleanly modularized.