I'm no fan of either Twitter nor Elon Musk, but this is a great move and I hope other companies follow what Twitter did here and start open sourcing more core parts like this. Maybe it's mostly useful for learning how it works, not for directly using it in your own product, but the amount of transparency it gives users cannot be understated. As long as that actually is the code they run, but there would be no way for anyone but Twitter to verify that.
I think it mainly helps with accountability regarding free speech. They did and do several kinds of shadow banning and down-boosting to combat spammers, which always has some false positives. If you the algorithm is published, you could at least better judge and argue when you are unfairly "silenced". Since this may be due to an avoidable flaw of the algorithm instead of some accepted collateral damage.
