Nothing is keeping it as a demarcated space other than the same conventions that you would have to follow anyway if you followed a "minimal subset" approach. Yo

Nothing is keeping it as a demarcated space other than the same conventions that you would have to follow anyway if you followed a "minimal subset" approach. You could easily write a Gemini client that handles application/javascript. In fact if this protocol got any level of popularity, I would expect that to happen extremely quickly.