[justinmk]

We may mention them in `:help news-breaking` for visibility, but that's only because I don't care about pedantry. API breakage != UI changes (e.g. mappings).

[tovej]

API breakage != UI breakage, yes, ofc. Because API != UI.

But the UI is also an interface, and the user is part of the total system. That system interface is broken if you change default mappings.

It doesn't matter if the interfacing component is software or a user.