allow other apps to make Ring calls (intents of/for other apps to set up calls?)
For external (non-voip) apps, supporting Ring would require:
On the externally "calling", sending side, the possibility to fetch the own local ring id (from ring or address book), to include it in a call request sent through external means.
On the receiving side, the possibility to pass an intent to Ring that lets Ring immediately start a call to the passed id.
As calls go p2p, what would another app have to do to open ring and initiate a call? https://github.com/nextcloud/talk-android/issues/96
Possibly you've already thought of making some sort of intent (sequence?) available to allow other apps to open calls.
If the other app can pass IPs or TURN server to meet, maybe this could even work in an ad-hoc signalling manner, without requiring a dht ring account id.