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 Magic Docs feature — which automatically updated # MAGIC DOC: files based on conversation context — has been completely removed. This includes the update prompt, the template system, and the background agent that processed magic doc files.
Evidence
Removal of magic doc infrastructure (search for "MAGIC DOC" in removed section)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.