[desdiv]

> Was there some notification of this change sent directly to all github users? I checked email and didn't find any references to the change from github.

Same here. No notification email as far as I can find. (Through this might depend on your notification settings? I have mine set to the minimal.)

>Is there some other automated system to become aware of changes like this, other than stumbling upon a HN post?

Github offer the web changelog, their RSS changelog, and the Twitter account @GHchangelog. These three all relay the same information, and ironically all three missed announcing this important change. Instead they posted a blog post[0] which was not linked at all by the changelogs.

So to answer your question: you need to follow all updates on both https://github.blog/changelog AND https://github.blog.

[0] https://github.blog/2021-09-01-improving-git-protocol-securi...