This is being worked out. It can represent the SW-PROT FEATURES, and is being linked to the sequence. It is also capable of representing SITE, HELIX, etc from PDB.
The SWISS-PROT description is given in the content.
We suggest the using the BUILTIN=KEYWORD option for XVAR where possible, (or DICTNAME) to hold content like "ACTIVE SITE".
FEATURE uses the DICTNAME and CONVENTION attributes and so can resolve ambiguities of terminology.