The “name” attribute is never allowed on the “meta""” element.

A <meta> tag has stray quote characters right after its name, as in <meta"" name="description">, so the parser reads them as part of the element name.

In a start tag, the element name runs until the first space, / or >. With no space between meta and the quotes, the browser creates an unknown element called meta"" instead of a <meta> element. The name attribute isn't allowed on that unknown element, which is what this warning reports. Single quotes (<meta'') or a different number of quotes give the same message.

The warning is the mildest part of the problem. Because there is no real <meta> element, the description, viewport or other metadata in the tag never takes effect, and search engines don't see it either. The unknown element also ends the <head> early, and since it has no end tag, it wraps the rest of the page. Expect several errors on the same line in the report, including one that calls meta"" a completely unknown element and a "Stray end tag" error for head.

Remove the quotes so that a space follows meta. If a template or CMS writes the tag, fix it there: the quotes can come from an empty variable or attribute printed right after the tag name. Correcting the tag also clears the other errors it caused.

Invalid example

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>My page</title>
    <meta"" name="description" content="A short summary of the page.">
  </head>
  <body>
    <p>Hello, world!</p>
  </body>
</html>

Valid example

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>My page</title>
    <meta name="description" content="A short summary of the page.">
  </head>
  <body>
    <p>Hello, world!</p>
  </body>
</html>

Learn more:

MDN Reference

MDN Web Docs: <meta> element

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MDN Reference

MDN Web Docs: <meta> name attribute

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WHATWG Spec

HTML Standard: Parsing HTML documents

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