From the LSG draft:

Warn (orange) conveys to the user their action may fail or have serious consequence but are not destructive. Some examples could be that an edit is likely to encounter an automated block due to the nature of the content, or that a preference is being reset to a default options.

Needs colours from May.

Color swatches: trello.com/c/IRqbu8p4/15-color-swatches