What
The formatter for error messages coming from a client has changed. Before, it added a Client ...: label to the front of the text. It now removes two kinds of leading label from the text, including that Client ...: one. If nothing is left after that, it shows a fixed fallback message instead of an empty one.
Why
This changes how error text from a client is shown, so the same label should not appear twice and an error is never displayed blank.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The exact old wording could not be read cleanly, so the precise before and after behaviour is unclear.
Anthropic's release notes agree
Fixed a mod's Client that fails while drawn taking down everything the mod drew around it; it now fails alone and raises ui.fault