A11Y HTML5 Validator is a free Chrome add-on developed by Jusuf Azer. This add-on allows users to check their HTML Markup for web accessibility issues by applying a stylesheet that utilizes advanced CSS selectors. With A11Y, users can easily evaluate the quality and accessibility of a website's HTML5 by selecting one of the settings from the modal dialog.

The A11Y HTML5 Validator is a valuable tool for web developers and designers who want to ensure that their websites are accessible to all users. By highlighting accessibility issues in the HTML Markup, this add-on helps users identify and address potential barriers that may prevent people with disabilities from fully accessing and navigating their websites. With its user-friendly interface and easy-to-use features, A11Y HTML5 Validator is a must-have for anyone interested in creating inclusive and accessible web experiences.