DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.
The message shown when a model declines a request due to safety measures now reads "has safety measures that flagged something in this session" (previously "has measures that flagged something in this session"). The wording more clearly attributes the behavior to safety systems rather than the model generically.
Evidence
Wording change (search for "has safety measures that flagged something in this session")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.