Assuming Twitter is serious about publishing their feed algorithm [1], it's possible they're merely anticipating the EU's upcoming Digital Services Act which was finalized over the weekend. Among other things, the Act will compel large platforms to "make the working of their recommender algorithms (used for sorting content on the News Feed or suggesting TV shows on Netflix) transparent to users." [2]

Twitter's EU user base is probably [3] above the 45 million threshold that triggers the strictest transparency requirements under the Act. So perhaps they figure if they're going to be forced to disclose anyway, they might as well do it proactively.

[1] If it's even coherent to talk about their feed ranking system as a single algorithm — see the other comments in this thread.

[2] https://www.theverge.com/2022/4/23/23036976/eu-digital-servi...

[3] https://www.statista.com/statistics/242606/number-of-active-...