Final answer:
The reporting dimensions useful for improving website accessibility are Device Category and Language.
Step-by-step explanation:
The reporting dimension that would be useful to reference when rebuilding a website to improve accessibility is Device Category. This dimension provides information about the type of device being used to access the website, such as desktop, mobile, or tablet, which can affect the design and functionality of the site. For example, if a large portion of users are accessing the site from mobile devices, the website should be optimized for mobile viewing.
In addition, the Language dimension can be helpful for improving accessibility. It can provide insights into the languages spoken by the website's users, allowing for the implementation of multilingual features or the translation of important content into different languages.
The dimensions of Browser and All of these dimensions could also be relevant for understanding user behavior and making improvements, but they may be less directly related to accessibility specifically.