Hey π
Very fair question! Generally we don't try to bloat it too much.
That means that everything that goes into our e.g. java modules, should apply to almost, if not, all java teams. That means: sensible defaults, and provide the appropriate configuration options.
In practice, you generally see the team working a lot on core stuff like keeping libraries up to date, improve build tooling, and supporting the latest of Java/Python/... If there's a feature that's only applicable for a small number of teams, it doesn't go in here.
That said, we do quite some POCs, which then lead to porting and generalising the functionality over to it. Usually by the original authors, but having the benefit of having better support by the platform team across the org.
Hope that answers your question, but free to ask more π