ISO/IEC 18975-related issues

The Identity Resolver section makes several references to ISO/IEC 18975. I have provided a couple of PRs that fix the biggest issues (it does not only define structured path URIs, it is not equivalent to GS1 Digital Link). But there are other related issues that may or may not be important to members of the group.

• The sample URI https://resolver.sample-register.example/products/ABCD9876/items/1234 is, of course, a valid URL and could be used as a product ID. However, it does not conform to either the query string or structured path approach defined in 18975 as it doesn't use ISO/IEC 15459-based identifiers with either AIs or DIs. Like IEC 61406 it relies on the internet domain name to confer uniqueness on the product ID. It also relies on the domain name for persistence. If that's what's intended by the WG, then OK, but it has those characteristics.

• The new text overlooks the need for a resolver description file at /.well-known/resolver. Defined in ISO/IEC 18975, this is needed to distinguish an IDR from any other type of server. Domain names are sovereign over their URI space (see RFC 8820) so it's necessary to declare that it will behave in a particular way. One of my to do items is to write a persistent document somewhere that sets this out (other than the GS1-Conformant resolver standard which does so but requires "gs1resolver" as the file name which is not appropriate for the general case). That's likely to be a W3C Member Submission. Sidebar: ISO standards are irrelevant to internet standards and can't be normatively referenced (because they're not open).

I can offer a PR that addresses these issues but it seems too big without discussion and agreement with the group first.