Why must data.enumerated attributes have values that are legal XML names?
I can see why the name of something should follow naming rules, but why
"2D" and "3D" couldn't be used as @type values in, say, <measure>.
For @type of abbreviation or bibliographic id, you can use "NASA" or
"IBM" but not "3M".
The spec for lbl/@type in the dictionaries module says the value can be
"any string of characters, such as usage, sense_restriction, etc.," but
the datatype is data.enumerated, so "3rdWebster" or "1911Britannica"
can't be used.