The MIME Type appendix in XQuery 3.1 needs updating:

http://www.w3.org/TR/xquery-31/#id-mime-type

[[
This new media type is being registered to allow for deployment of XQuery on the World Wide Web.
]]

should now read, e.g.:

[[
This media type registration is to allow for deployment of XQuery on the World Wide Web.
]]

The example encoding declaration
   xquery version "1.0" ...
should say, xquery version "3.1" ...

Delete, Currently the version number, if present, must be "1.0"

Change
[[
The XML Query Working group is working on a facility to allow XQuery expressions to create and update persistent data. Untrusted queries should not be given write access to data.
]]

to be, e.g.
[[
The optional XQuery Update Feature allows XQuery expressions to create and update persistent data, potentially including writing to arbitrary locations on the local filesystem as well as to remote URIs. Untrusted queries should not be given write access to data.
]]

(these changes probably also apply to XQueryX)