What is the issue with the Infra Standard?

It's not currently specified how struct/tuple equality works. This is required, for example, for it to be well-defined how they work as map keys (and this is already done, see https://html.spec.whatwg.org/multipage/webappapis.html#module-map).

I think the obvious answer (and definitely what's expected for the module map) is that struct/tuple equality is structural - two structs/tuples are equivalent if they have the same shape, and the contents are equal.