Hi all,
    I've been reading the following XPath 3.1 F&O spec section, https://www.w3.org/TR/xpath-functions-31/#html-ascii-case-insensitive-collation (section 5.3.4 of the XPath 3.1 F&O spec).

This XPath 3.1 F&O spec section says following,

<quote>
The collation URI http://www.w3.org/2005/xpath-functions/collation/html-ascii-case-insensitive must be recognized by every implementation.

It is used to refer to the HTML ASCII case-insensitive collation as defined in [HTML5: A vocabulary and associated APIs for HTML and XHTML] (section 2.5, Case sensitivity and string comparison).
</quote>

The XPath 3.1 F&O spec within its normative references, provides following link to HTML5 spec : https://html.spec.whatwg.org/multipage/ (the one page HTML5 spec is following, https://html.spec.whatwg.org/).

I'm not able to find the, phrase "Case sensitivity" within the above cited HTML5 spec link (i.e, HTML5 spec's link as cited above, doesn't seem to have definition(s) related to "Case sensitivity and string comparison").

Due to the above stated facts, can an XPath 3.1 implementation as of now, omit complying to XPath 3.1 F&O spec spection https://www.w3.org/TR/xpath-functions-31/#html-ascii-case-insensitive-collation?