The sources of Dragonriding mount customization options that you have not unlocked yet are now visible directly in the Rostrum of Transformation.
Rostrum of Transformation is a place where you customize your Dragon Isles Drakes. Simply put, it’s a “Barber Shop” for drakes.
The customization options are unlocked by participating in a variety of Dragonflight content — quests, Renown, Professions.
A small but welcome addition was implemented in the latest Dragonflight Beta Build. You will now see a source next to the customization option that you have not unlocked yet.
In our specific scenario, the green drake’s spiked tail option is gated behind Centaur Renown.