The columns of the grid are:
File Name
The full pathname of the selected file.
Current Size (MB)
The current size of the file, measured in megabytes.
Max Size (MB)
The maximum size for this file as configured for Spotlight in Configure | Monitored Files. Setting the maximum file size in Spotlight does NOT prevent the specified file from growing beyond this size. However, if the size of the file exceeds that maximum size, Spotlight raises a critical alarm.
% Max Size
The current size of the file, measured as a percentage of the maximum size.
Severity
The degree of urgency associated with the current size. The severity controls what action Spotlight takes. (For example, if the size of the file exceeds the maximum size, the severity becomes critical, and Spotlight raises a critical alarm.)
File Exists
Whether or not the file exists at the specified location.
Configure Spotlight to track the growth of files
From the Spotlight Client, click Configure | Monitored Files.