Hey, the Chirr App author here! I released the initial version of the app in 2017 as a free and open-source tool ( https://github.com/kossnocorp/chirrapp ) even before Twitter threads become a thing. Later that year, Twitter gave me a lot of trouble when they added 280-chars support but didn't update API and the twitter-text library. I was about to close it, but thanks to Firebase, the running cost was $0, so I fixed…
How does editing work given Twitter doesn't support editing tweets? Looking at the demo ( https://twitter.com/chirrapp/status/1282608419321643009 ) I think it removes the tweet you edited AND any later tweet in the same thread, and republishes those - the first with updated text, and the rest with the same content as before. Is that right?
I'm also working on adding a delayed publishing like in GMail, so you can edit typos even before the thread got published.