Before I ask my question I need to get some info out of the way.
I am the maintainer of the YARG APWorld over in the Archipelago community. (info on AP: https://archipelago.gg/) The AP Discord has rulings regarding age ratings on any game that gets an implementation on their server. Any game that goes above an 18+ rating has to be moved to a different server. (Still an official server, just one that is age gated)
The way that they determine age rating starts at official sources. (ESRB, PEGI, USK, etc.) If a game does not have an official rating from a source like that, second in line is the developers/publishers. They also only recognize the difference between 18+ or not.
This brings me to my question. For the content available through the YARC Launcher, (YARG OST, DLC, and YARN) would the team consider the game to be 18+?