"On the evening of March 8, we logged out all users from GitHub.com who had logged in prior to 12:03 UTC on March 8. This was done to protect users from an extremely rare, but potentially serious, security vulnerability affecting a very small number of GitHub.com sessions. No user accounts were affected"

I really couldn't simplify much without losing information. Logging out users isn't the same as invalidation of authenticated sessions because this probably revoked access to bots / API calls etc.

Last night, we logged out your Github account to fix a security flaw. Your account was not breached. You can read more details here [1].

[1] https://github.blog/2021-03-08-github-security-update-a-bug-...

"On the evening of March 8, we invalidated all authenticated sessions on GitHub.com created prior to 12:03 UTC on March 8 out of an abundance of caution to protect users from an extremely rare, but potentially serious, security vulnerability affecting a very small number of GitHub.com sessions."

"Out of an abundance of caution" adds only the smell of a desperate attempt to reassure the reader. The sentence would be much better without it.

I like rich language where it is useful or fitting but, usually, I only want to know what the writer is communicating.

Hmm. You may be right.

like this:

> Hmm. You may be right.

thats all i ask

Mandarin was the official language of the government, and so all regional and local bureaucracies, during the days of dynasties in China. Although it may sound foreign to locals in various provinces, it guaranteed that every part of the government had a common understanding.

Quite the opposite of fluff for fluff's sake.