When you use the CSS paged media feature to create the PL and PS specs, you do not only need the usual PL and PS files but also the at_xxxx.css and the at_xxxxx.map files in order for things to work correctly.
Pathfinder currently does not give you any possibility to view/manipulate the at_xxxxx.map file although that file is now part of the style definition.
Why is this important?
Suppose you did some local style development so you end up with a local PS, PS files + local at_xxxx.css and at_xxxx.map files.
You now decide to move your styles to the library level.
So you move the local PL and PS files to your library.
If you are clever enough you will not forget to move the at_xxxx.css file to the library as well.
But since pathfinder does not show you the at_xxxxx.map file, you have no way of moving this in the library.
Result: Things do not work.(except for the one job in which you did the development)
Suggestion: include BOTH at_xxxx.css and at_xxxx.map files in the window that allows you to manipulate either the local or library level style files.
It makes sense to show both the .css and .map file since both belong to the PL/PS file you want to manipulate.
As the user most probably wants to move/delete/copy these files as well.