What the commenter above was referring to is special API access for Nokia and a few key third-parties that regular devs were not allowed to use.
It was a strange time for Windows phone. Agreed, such a shame, it was an interesting UX-first design for its time.
Wow, you came to the Jellyfin community to write a long comment saying “I don’t know what this is and I don’t care”?
You don’t have to care!