The paragraph beginning "As indicated by italics" in section 3.3.8 Codings seems to be referring to an italicized notation convention. The link goes to the Notational Conventions section, but I don't see anything there that uses italics, the syntax description the paragraph is describing doesn't have italics, and it doesn't appear to be used anywhere in the documentation.

It's not clear what this is referring to, and perhaps more importantly the aspect being documented, optionality of the version and display specifiers in the syntax, is somewhat unclear as a result.