@hrefna
> there's not even a registry or a good way of saying "I am using these extensions"
I may be late to the party in mentioning this, but as of fairly recently there is the FEP process for standardizing extensions, which is a step in this direction. Sounds like we need an FEP for signalling which FEPs a server supports, maybe someone has already drafted one?
https://codeberg.org/fediverse/fep