Does Chrome use XPath 2.0?
No, Chrome uses XPath 1.0.
You can simplify your XPath expression to just a v2.0 function to see this:
$x("lower-case('ABC')")SyntaxError: Failed to execute 'evaluate' on 'Document': The string 'lower-case('ABC')' is not a valid XPath expression.Trying any other XPath 2.0 function such as current-date() will yield a similar error.
There is no built-in way of definitively determining the version of an XPath implementation other than by such probes.
XSLT, on the other hand, has system-property('xsl:version') for determining version 1.0 versus 2.0.
Google Chrome (or Chromium) still uses libxml2 thus is limited to XPath 1.0. Cf. this Readme from the source.