well, I assume by syntax you mean Gemtext (which I like a lot, my personal blog is built on top of it), so I think it might work for twtxt clients...

I knew of twtxt in Gemini Antenna, so at least the 2017 spec might work on that protocol. I think the main issue with extensions is that they weren't designed with many URLs and protocols in mind.

Also I have to admit that the Gemini community significantly reduced in the last few years. I don't know how worth it is to add support for Gemini now.