A couple of weeks ago, I proposed to change our PHP data model bindings to allow extra info to be attached using the concept of "facets" simmilar to the "role object" and "extension object" pattern.
Code experiments showcasing this idea can be found on github: * https://github.com/wmde/WikibaseDataModel/pull/576 * https://github.com/wmde/WikibaseDataModelSerialization/pull/174
This is the final call for objections against using this approach. The rationale behind it can be found on https://phabricator.wikimedia.org/T118860 and related tickets.
Implementation details can still change later, but after nearly 3 months, we finally need a decision on the conceptual level. If there are no substantial objections, this will become definite on Tuesday, December 8.