@eapl.me@eapl.me Just responding to some of your specific ideations here:

Sure! From my research, Gemini (and likely Gopher as well) don’t have a similar header, so if a client is using those protocols, they won’t be able to inform your server.

So, it’s worth considering, would twtxt 2.0 only support HTTP/S?

I’m not sure how to standardize “Discovery” across different protocols for serving feeds, HTTP, Gopher, Gemini, etc. beyond what you initially suggested. But here’s the thing, the User-Agent HTTP Header isn’t the only aspect to “discovery”. Discovery in practise is more of an organic property of @-mentions across feeds in the first place, something that crawlers take advantage of.