Right now the scope of both the F & Tag fields is the sub-attribute, since they occur to the right of the Extended Type. This allows 1) very long sub-attributes and 2) the grouping of sub-attributes within a larger extended attribute. Do we want to leave it this way or enlarge the scope of one or both fields to encompass the entire extended attribute?
[gwz]
[gwz] To answer my own question, I think that it would be better to make fragmentation & grouping apply to entire extended attributes, rather than sub-attributes. This reduces flexibility, but simplifies the semantics considerably, I think.