Namespace-specific warning pragma example in user guide?

In section 6.3.4.3 of the GHC 9.14.1 user guide (the same text dates back to earlier versions), I am puzzled by the example of a namespace-specific warning: https://downloads.haskell.org/ghc/9.14.1/docs/users_guide/exts/explicit_name... type family Head xs where Head (x : _) = x pattern Head x <- (head -> x) {-# WARNING in "x-partial" data Head "this is a partial type synonym" #-} The text string refers to a type synonym but the namespace tag is "data". Which is it, and what's an example in which the intended warning would be issued? -- Viktor. 🇺🇦 Слава Україні!