Structured annotations are allowed (property=value)
URI
Condition under which issue is included. True by default.
or parents? refinement-id, node-id or some other suitable scoping
node within the outer scope which a restricted refinement applies to
Statement - node pattern in node grammar - may refer to variables.
Condition under which refinement can be used. True by default if not specified.
Condition under which constraint applies or must hold. True by default.