The CSS WG has published an updated Working Draft of the Media Queries Level 5.
Media Queries allow authors to test and query values or features of the user agent or display device, independent of the document being rendered. They are used in the CSS @media rule to conditionally apply styles to a document, and in various other contexts and languages, such as HTML and JavaScript.
Media Queries Level 5 supersedes previous levels, and in introduces a broad range of new media features, both to better detect the characteristics of the environment as well as the preferences of the user.
This update leaves the fundamental media queries mechanism unchanged, but brings significant revisions, addition, and even deletions to the supported media features. Significant changes are detailed in the changes section.
The CSS-WG is likely to start stabilizing this feature-set soon, so while things may still change somewhat before we reach Candidate Recommendation, now is likely a good time for in-depth review for those that can tolerate a moderate amount of changes.
Please send feedback by either filing an issue in GitHub (preferable) or sending mail to the (archived) public mailing list www-style@w3.org with the spec code ([mediaqueries-5]) and your comment topic in the subject line. (Alternatively, you can email one of the editors and ask them to forward your comment.)