Which group is considered a major user category in WCAG 2.1 enhancements?

The choice of users with cognitive or learning disabilities as a major user category in WCAG 2.1 enhancements is correct because WCAG 2.1 explicitly expands the guidelines to address various needs and challenges faced by this group. The enhancements aimed at this category include specific criteria designed to improve accessibility for users who may struggle with understanding complex navigation, text, and interface components. This focus helps create a more inclusive web experience for individuals with cognitive or learning disabilities, ensuring that content is presented in a clear and understandable manner.

The other options refer to groups that do not align with the specific focus of WCAG 2.1 enhancements. Users with high-speed internet do not face accessibility challenges that the guidelines are designed to address, as internet speed primarily pertains to performance rather than usability. Web designers and developers are key to implementing accessibility best practices, but they do not represent a user category. Similarly, IT accessibility testers play a vital role in ensuring compliance with accessibility standards but do not fall into the user category that WCAG addresses directly. This emphasizes the importance of focusing on the needs of actual users in the context of web accessibility, thereby making the selected answer the most appropriate in the context of WCAG 2.1.