From HTML WG Wiki
The following in an unordered list of features identified to be at risk for inclusion in the HTML 5.0 set of specifications. Over time this list may be refactored into multiple pages, with this page remaining for navigation purposes.
- <command> and commands API
- <menu> and context menus feature (“contextmenu” attribute)
- <input type=color>
- <input type=datetime>, <input type=month>, <input type=week>, <input type=time>, <input type=datetime-local>
- <style scoped>
- <iframe seamless>
- Custom scheme and content handlers (registerProtocolHandler and registerContentHandler)
- Outline algorithm
- UA mechanism for navigating to resources linked to in cite="", see Bug 18915 for more.
- appcache (cf HTML f2f November 1 discussion)
- <a media> and <area media> - these media queries are not used