I agree that would be a handy KM enhancement.
Meanwhile, you can easily do this with a JavaScript in Browser with just a few lines of script. For example:
'use strict';
(function run() { // this will auto-run when script is executed
var xPath = document.kmvar.DLE__XPath
var nodes = document.evaluate(xPath, document, null, XPathResult.ANY_TYPE, null)
var result = nodes.iterateNext();
var statusStr = (result) ? "[FOUND]" : "[NOT-FOUND]"
return statusStr;
} // END of function run()
)();
To use this, you need to first have set the KM Variable "DLE__XPath" in a prior action:
You can test this particular XPath on this page:
https://forum.keyboardmaestro.com/latest