How can I tell what 'columns" are in $L.file?

So in HPSM, lots of conditions and fields, etc are based around "something in $L.file" or one of the alternative structured records.

 

When I try to look for details of what the values are in the $L.file , I can see _values_ in the RAD debugger by saying

display $L.file

but that doesn't help me figure out how to access a specific value.

 

Where can I find a description of each field in the structured records such as $L.file?

 

They are obviously in some order, and I know that there are "columns" like brief.description, etc.

is there a RAD debugger command that would print all the column names out?