Multiple <h1> tags
This means that the URL in question has multiple <h1> elements.
Why is this important?
The header 1 (h1) tag is considered important to help both users and search engines to quickly understand what content they can expect to find on the page. It is considered best practice to try and include the main target keywords for the page in the h1, whilst also communicating 'what the page is about.'
Having more than one <h1> tag can be a sign of poor content structure, and could de-emphasize keyword associations with the page.
What does the Hint check?
By default, this Hint will trigger for any internal URL which contains a <h1> tag multiple times.
Examples that trigger this Hint
The Hint would trigger for any URL with a <h1> found in the <body> more than once:
Why is this Hint marked 'Potential Issue'?
This Hint is a 'Potential Issue', which means that it is unlikely to be affecting the site at the moment, but should be investigated as it could cause issues in the future.
Firstly, the SEO value of a <h1> is debatable, so some users may already feel that this is a non-issue.
Furthermore, with HTML5, you can use multiple h1 tags and still have a well-structured, semantically accurate document. So this Hint exists to draw your attention to the situation, so you can investigate further and determine if you think there is actually an issue worth fixing.