This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
When an HTML5 document is submitted for validation that contains an hellip entity, the following error is given "reference to undeclared general entity hellip." This does not occur on validator.nu, and according to the list of named character references (http://www.w3.org/TR/html5/named-character-references.html), this is still valid.
If you're seeing the message "reference to undeclared general entity hellip", it's because your document is being parsed as "XML; don't load external entities" instead of HTML. So you may need to manually set the validator to one of the HTML5 presets (instead of the XHTML5 ones). I don't know why you'd be seeing different behavior between the W3C Nu Validator and the validator.nu, but if you can point me to a URL I can check with, I'll do that.