Is fragment directive a concept, a member, or both?

[annevk]

Per its definition it belongs to document, but when you read something like

The text fragment directive is one such fragment directive

it seems that it should probably be its own concept as well. And document's member holds that concept?

[bokand]

I think so? Is "concept" a formally defined term or do you just mean that we need a definition outside of a member definition?

[annevk]

That's what I mean, yes. (Concept has no formal definition.)