Show me a paper standard other than ISO 216, aka the international standard for paper size, that uses "A4" as the indicator for its default letter size.
DIN 476 does use the same indicators. Of course that's just the original German standard that ISO 216 was based on and defines the exact same sizes, so it really doesn't matter. (Also it is superseded by DIN EN ISO 216, which is just ISO 216 backported.)
Making sure we are technically correct is appreciated, thank you.
But yes, that's a bit of a "structural vs nominal typing" distinction, and we seem to agree that a "structural typing" interpretation makes most sense here.
