I would like to add material to the manual, detailing the differences between the XPath 1.0 language supported in PG, and the XQuery/XPath 2.0+ expected by the standard.
A good preview of what that would look like is the "related to version of XPath" wiki section at [1]. That wiki section (minus the two inside-baseball paragraphs about commit 3963574 and its reversion) comes to a bit under 400 words. So that's roughly the amount of material I'm thinking to add. Where should it go? I have thought of: 1. A new sect2 near the top of the "functions-xml" sect1. This makes sense because the material applies to all the functions below that involve XPath. But that seems like the wrong place for 400 words of gory details. 2. A short remark at the top of functions-xml, linked to a footnote with the gory details. But that would be a long footnote. The longest currently is a footnote with 101 words in the start tutorial. 3. A sect2 at the very end of functions-xml, linked to from a short remark at the top. 4. A new appendix, or a new conformance section in the features.sgml appendix, linked to from a short remark at the top of functions-xml. Or is there an even better idea I have not thought of? -Chap [1] https://wiki.postgresql.org/wiki/PostgreSQL_vs_SQL/XML_Standards#Related_to_version_of_XPath
