What would a Twitter “App Store” look like?

I've been thinking lately about Twitter's monetization model; the way they closed their API and undermined the work of so many developers years ago. And now that Elon will purportedly purchase it, there's been a few people discussing different ways to change it.

One interesting suggestion was by Stephen Wolfram, where he tweeted about a Twitter "App Store" where you could install third-party feeds. And it got me thinking, what else would this App Store have?

I'm a staunch believer in bottom-up processes cultivating innovation. Some of the best games, discoveries, and inventions were a mixture of trial and error and thorough observation because some random person was tinkering here and there.

Obviously there's more to innovation than just accidents, but an open place where people can play and experiment and install new "apps" or "plug-in's" sounds immensely interesting.

Off the top of my head, it would be amazing if one could install a LaTex module, so people who wanted to express complex mathematical expressions could do so.

Or have a custom feed with a slider bar so you can adjust just how much negative and positive sentiment you want to see, where -1 is 4Chan levels of cynicism and 1 is Sesame Street; the point being users can choose just how much vitriol they want to expose themselves to.

Or having the ability to request money to have an question answered with a bounty.

Example:

Tweet: "I recommend everybody take long walks. Great for your health!"

Reply: "Do you have any book suggestions?" attached with a $1.99 bounty for answering.

These are just suggestions. I'm not necessarily looking for whether or not an App Store is a good or bad idea, but as a hypothetical, if it existed, what would it look like in practice.