Sys User role mapping shows a matrix of system users and groups vs system roles. The back button in cell A1 will go back to the summary worksheet.
This will be seen in the Excel file if the option Show System Task /Role Mapping is selected.
In this screenshot is included the role descriptions- these are stored as comments. (see the red icon in the top right of the cells). Hovering over the comment red triangle will show the role description:
To view comments check the box