[Implementations] Note that Saxon 10 offers higher order function support in HE edition

[joewiz]

https://xquery.forhumanists.org/implementations/#xquery-coverage-in-saxon

https://www.saxonica.com/products/feature-matrix-10.xml

Also add the link to the open source edition's code repository: http://dev.saxonica.com/

[joewiz]

Also note that only PE/EE support the EXPath File, Binary, and Archive specs: https://www.saxonica.com/html/documentation/extensions/functions/expath.html

From xml.com Slack:

• File: a third-party implementation for Saxon HE: http://cxan.org/pkg/expath/file-saxon
• File and HTTP Client: Extension functions for Saxon HE 9.9-10.3 written by Maarten Kroon: https://github.com/Armatiek/saxon-extensions