Where are the warnings?
The archive is effectively warnings-optional. Some of the more major warnings are included as categories, and most authors will likely use those if they’re appropriate to the story, but no author is obligated to do so. However, authors can choose to include warnings if they wish by putting keywords in their Author’s Notes. This is the place to add not only separate major warnings (e.g., ‘graphic torture’), but also warnings for things like minor het or slash content, death (of a minor character), etc. But again, any such warnings are totally optional.
