I have recently been working with XPath and have been searching for information on which browsers support XPath 2.0 without much luck. The best I could find was the query te
I do not know of any, and the official list of implementations doesn't include one either.
An alternative - of course less performant than a native implementation - would be XQIB which is an XQuery implementation in JavaScript. XPath 2.0 is fully included as a subset in XQuery 1.0, so you will be able to use all XPath 2.0 features (and more) in all browsers with JavaScript support.
A short sample taken from their website on how to use it: