What is the purpose of ATAG?

The purpose of ATAG, or the Authoring Tool Accessibility Guidelines, is to ensure that authoring tools provide support for creating accessible content. This involves establishing guidelines that help developers and publishers of authoring tools to incorporate features that facilitate the development of accessible web content, thereby promoting inclusivity and usability for people with disabilities. By following ATAG, developers can design tools that not only assist in content creation but also include accessibility checks and features that allow for the production of content that adheres to accessibility standards.

The other options do not pertain to the primary objective of ATAG. For instance, prohibiting the use of social media does not relate to accessibility in authoring tools. Similarly, standardizing web programming languages and creating uniform accessibility standards for all devices are broader efforts not specifically targeted at the functionality and support provided by authoring tools in relation to accessibility. Thus, the focus of ATAG on supporting accessible content creation is what makes the correct choice stand out.