The playable-specialization endpoint allows retrieving talents and pvp talents (along with relevant spell IDs) for a class specialization.
It would be useful to also obtain a list of spells that are available to a particular specialization by default (similar to the spell book in-game). This can help us in creating apps where we can share spell button layouts, for example.
We can either include all spells castable by a specialization via the playable-specialization response, or choose to include “baseline” class spells in playable-class and the rest with the spec.