Binary package “w3c-markup-validator” in ubuntu oracular

W3C Markup Validator

 This is a CGI script which lets you enter the URL of a web
 page which will be then checked against a validating SGML parser for
 conformance to official W3C recommendations. Pages can also be uploaded.
 .
 These are the same scripts that are available on the W3C web site,
 http://validator.w3.org/.