From the documentation page:
BaseX is both a light-weight, high-performance and scalable XML Database and an XQuery 3.1 Processor with full support for the W3C Update and Full Text extensions. It focuses on storing, querying, and visualizing large XML and JSON documents and collections. A visual frontend allows users to interactively explore data and evaluate XQuery expressions in realtime. BaseX is platform-independent and distributed under the free BSD License (find more in Wikipedia).
Besides Priscilia Walmsley’s XQuery 2nd Edition and the BaseX documentation as a PDF file, what other XQuery resources would you store on a smart phone? (For occasional reference, leisure reading, etc.)