The R4.3 specification introduces more detailed API modeling bundle revisions and wiring. Rather than just facading our existing abstractions for these concepts, we should modify the framework implementation to adopt them wholesale (i.e., replace our existing abstractions with the spec'ed abstractions). Although the standard abstractions do not map one-to-one with our existing abstractions, they are reasonably close and the benefit of having an implementation that is consistent with the standard API probably outweighs the cost of changing, since very few people actually depend on our internal API.
This issue will only be used for this internal refactoring process and generally will not be used as the issue for implementing new R4.3 functionality. We'll try to introduce separate issues for new any new functionality to make the change log more meaningful.