Discussion of the issue is available in Issue 75. To file comments on this proposal, please raise new issues for each discrete comment in GitHub.
When content becomes visible when triggered by a user interface component receiving keyboard focus or pointer hover, the following are true, except where the visual presentation of the content is controlled by the user agent and is not modified by the author:
Examples of additional content controlled by the user agent include browser tooltips created through use of the HTML title attribute.
Custom tooltips, sub-menus, and other nonmodal popups which display on hover and focus are examples of additional content covered by this criterion.