While I do think Twitter is basically done as a serious open source contributor, there was one final comment that I kinda wish had been included:

"But on the other hand, open source is designed to be resilient. The fact that we can be grateful to the amazing Tweeps that have contributed over the years, and then fork the project and give it new life without Twitter, is open source working exactly as intended."

I'm very optimistic those projects can find new homes.

https://www.zdnet.com/article/twitter-turns-its-back-on-open-source-development/