Link type management/IANA

Created by: philarcher

In text such as https://github.com/uncefact/spec-untp/blob/DAC-Updates/website/docs/specification/IdentityResolver.md, there are many mentions of link types. That specific text refers to link types like untp:dpp. That is, a CURIE in which the prefix untp is some stub and dpp is the specific term.

It's worth noting the existence of IANA's registry of link relation types. Relation types listed there (such as prev and next) can be used on the Web without any prefix. The relevant RFC on Web Linking defines an extension mechanism through which anyone can define their own link relations. These must be declared using URIs. It is my own personal interpretation of text in section 2.1.2 that says

Note that while extension relation types are required to be URIs, a serialisation of links can specify that they are expressed in another form, as long as they can be converted to URIs.

I take this to mean that CURIEs can be used. However, it's slightly risky since there's no way to define what the URI stub is for which the prefix is a substitute. Therefore, I suggest the group consider registering the link relation types it considers important with IANA so that they can be used without any prefix and without UNECE having to publish and maintain its list.

For reference, a near-future task of mine is to register at least some of the GS1 link types in this way with IANA