Issues exporting terms

We just went through the process of exporting terms/elements/attributes from the EPUB 3.3 specification, so wanted to share a few of the issues we ran into:

First, it would really help to have the element and element-attr definition types documented. I didn't realize these existed until I was looking up the exported terms in the xref database and followed some html examples through to the source markup.

Second, it's not clear when or how data-dfn-for works for elements and attributes. It appears for attributes you can specify tbe element name and then you can reference as [^elem/attr^]. This is incredibly useful for avoiding naming collisions, but it doesn't appear to work well for elements. The EPUB specification defines multiple grammars - package document, media overlays, container file, etc. These grammars have some elements whose names collide, but I couldn't find a way to make data-dfn-for work to indicate that elements belong to different grammars.

For example, if I put data-dfn-for="package" on the package document's metadata element and data-dfn-for="smil" on the media overlays version, I was able to write [^package/metadata^] and [^smil/metadata^] internally, but the definitions didn't export so in any other document I'd get a message that the element "metadata" for "package" was not defined in any referenced specifications.

In the end, I had to skip defining the lesser-used elements to avoid collisions.

Third, is it a bug that you can't use the <a data-lt="..."> syntax for attributes or a missing feature? For example, writing [^script/src^] is fine but <a data-lt="script/src"> results in an error.

In any case, the [^...^] syntax would be helpful to note in the linking shorthands section. I didn't spot the link to the other shorthands after the example, so it confused me initially when you use [=...=] and when [^...^].

That's everything I can think of right now. Any other issues I missed @iherman?

Start with the linking shorthands section in the Respec documentation and reproduce the EPUB export examples using element, element-attr, data-dfn-for, and data-lt. Trace the generated definitions through the xref database and source markup. Done means the requested behavior is clarified or supported and the relevant definition types and shorthand syntax are documented.