Dear kstang,
There's a relationship between functionalities and roles, for example, DEV functionality is related to users with DEV role (developers).
In general, functionalities are listed as follows.
DEV permission: it is for developers, it allows you to create and edit documents that are in DEV status
TEST permission: it is for testers, it allows you to run doc that are in TEST status
EXEC permission: it is for everyone, it allows you to run doc that are in RELEASED state
CREATION permission: it is for end users, it allows you to create documents in that folder
Regards
Matteo