qtspecs
XSLT and XQuery Specifications - the source used to build the specs, and the errata
Individual specs can be found under specifications; you can view them at htmlpreview.github.io, e.g. with http://htmlpreview.github.io/?https://github.com/w3c/qtspecs/blob/master/specifications/xslt-30/html/Overview.html or https://htmlpreview.github.io/?https://github.com/w3c/qtspecs/blob/master/specifications/xquery-31/html/xquery-31.html