This definition appears very rarely
For these cases, it is important for user agent developers to consider the application of another W3C-WAI Recommendation, the Authoring Tool Accessibility Guidelines (ATAG). ATAG (currently 2. 0 is in draft) provides guidance to the developers of tools regarding the accessibility of authoring interfaces to authors (ATAG 2. 0 Part A) and ways in which all authors can be supported in producing accessible web content (ATAG 2.