Missing closing bracket in XML Representation?

[himorin]

https://www.w3.org/TR/ttml2/#profile-vocabulary-extension
6.1.5 ttp:extension has XML Representation as:

<ttp:extension
  extends = xsd:string
  restricts = xsd:string
  value = ("optional" | "required" | "use" | "prohibited") : see prose below
  xml:id = ID
  Content: #PCDATA
</ttp:extension>

which does not have closing bracket right before Content: #PCDATA. Is this valid? (I'm quite not sure...)

[nigelmegitt]

Every element's representation looks like this in the whole specification. The word "Content" is italicised. Putting a close angle bracket before "Content" would suggest that the text "Content: XYZ" is the required element content.

I would suggest closing with no change.

[skynavga]

Ditto what @nigelmegitt said. The XML Representation syntax is a meta-level syntax used to formally describe the element vocabulary of TTML. It is not itself XML syntax. It is based on the XML Representation syntax used in XML Schema Part 1: Structures Second Edition.

[himorin]

Thank you for confirmation!
I've wondered since ones in TTML1 has such bracket, so I was quite not sure why and what happened....

[skynavga]

Actually, I see what you mean (about TTML1). I don't recall when or why they were removed in TTML2, but I suspect they should be restored. Otherwise, it appears that the start tag is not closed.

[nigelmegitt]

I did not notice that difference to TTML1 either, and also cannot recall an intentional removal.