All frame or iframe elements in an HTML document must have a unique title, ensuring the content can be described to screen reader users.
Screen reader users rely on a frame title to understand the contents of the frame. Without a title attribute, navigating through frames and iframes can be difficult for users who rely on screen readers.
Screen reader users have the option to pull up a list of titles for all frames on a page. With the help of unique titles, users can find the frames they need more easily.
Ensure all frame and iframe elements have titles that are not repeated. Titles should also be brief, clear, and informative.
It’s also best to give the enclosed document a title element that’s identical to the title attribute. This is because some screen readers will replace the contents of the title attribute with the contents of the title element inside the frame.
For more examples, visit W3C’s GitHub’s ATC Rules library.