So, rather than calling it non-linear, which is clearly somewhat confusing, perhaps it would be more clear to state that it handles affine functions like F to C...?
Agreed. Why they wasting our time pointing out it’s “non-linear” when this statement is only true for some definitions of linear? Just pick a non-ambiguous word, or add an asterisk and footnote.
Perhaps. That's what I myself did when adding handling for affine unit conversions in a project I worked on.