W3C XML Query Use Cases contains the following use cases:
1. Use Case "XMP": Experiences and Exemplars
2. Use Case "TREE": Queries that preserve hierarchy
3. Use Case "SEQ" - Queries based on Sequence
4. Use Case "R" - Access to Relational Data
5. Use Case "SGML": Standard Generalized Markup Language
6. Use Case "STRING": String Search
7. Use Case "NS" - Queries Using Namespaces
8. Use Case "PARTS" - Recursive Parts Explosion
9. Use Case "STRONG" - queries that exploit strongly typed data

Use cases 7 and 9 are not supported as they would require
special support for XML namespaces and XML Schema,
both of which are outside of scope of magic/xml.

Of the rest 1, 2, 3, 4, 5, 6, 8 are coded.