We should recommend a way to provide multiple arbitrary classifications to *Spec elements (e.g. elementSpec).
Two possibilities occur to me instantly:
A) Encourage use of @ana for this purpose pointing to a taxonomy
B) Introduce <keywords> as an allowed child of *Spec to allow terms within that to be used.
The use case is to classify elements according to any user-defined or other classification system to allow for more flexible use. e.g. the TEI-C XSLT has a function that hard codes guesses as to whether a particular element is used \'inline\' or not. but there could be a <term>inline</term> on all such elements so that this kind of magic was unnecessary. Similarly, ODD writers may wish to categorise elements for other purposes \"These are all the date-related elements from various modules\", or other more semantic or folksonomic groupings.