I think you’re reading this too literally. They likely just mean file scope from a purely usage perspective. I.E. you only use the variable in one file, it doesn’t matter how the language processes it into a computational scope
A human typed in something less precise than you'd like in a style guide. Find a bug tracker to request a verbiage change. It's not that big of a deal.
No one is asserting that variables are in fact file scoped.