On the specification page for an element is a field labeled "May contain". The value of the field is sometimes "Empty element".
John asks: '<ptr> is an empty element. That makes sense. But so too is <gi> and <datatype>, even though neither is, in XML's defined use of the term, an "empty element." Is "empty element" an idiosyncratic TEI term, meaning, I guess, "empty of further TEI elements"? Or is its appearance in, say, <gi> and <datatype> bugs in the documentation?'
Syd replies: 'Outright egregious errors in the documentation, I'd say.'
Lou replies: 'Well, not so much in the documentation as in the stylesheet which creates the documentation. At a quick glance the elements affected are those whose content models are expressed using datatype references (e.g. "data.name" for <gi>) rather than explicit content models so should be easy to catch.'
Sebastian replies: 'I agree, it's just a poorly-constructed test in the xslt trying to decide if an element is empty. Can't think how that slipped through.'