A layout in Relativity is primarily used for what function?

A layout in Relativity serves the primary function of holding fields and choices. It is an essential part of the document review process, as it allows users to organize how information is presented within a workspace. Through layouts, users can customize the display of document metadata and add fields that are relevant to their reviews, such as text fields, dropdown menus, and checkboxes. This customization enhances the efficiency and effectiveness of document analysis since it enables users to view and interact with the information most pertinent to their tasks.

The other options focus on functionalities that are not the primary role of a layout. Defining user roles is related to setting permissions and access levels which is managed separately in the user administration settings. Displaying user activity pertains to tracking usage and interactions within the application, which can typically be viewed through auditing features or reports, not layouts. Tracking software updates involves version control and release notes, aspects that are also managed through administrative tools rather than layouts. Thus, the layout's function as a holder of fields and choices stands out as integral to the user’s interface and experience in Relativity.