Considering accessibility
Sometimes, new authors need a gentle reminder to think about accessibility when designing and writing web pages and apps. Experienced authors need a quick way to look up the allowed ARIA roles, states and properties for each HTML element. Browser and Assistive Technology (AT) implementers need quick access from an HTML element to its platform accessibility API.
For a look at how these needs translated into the new Accessibility considerations section for each element, please see "POURing ARIA into the HTML element specs" over at 24 Accessibility.