Reference Cinema 4D Basic Features Configuration Preferences
Function available in CINEMA 4D Prime, Visualize, Broadcast, Studio & BodyPaint 3D

Plug-ins

Plug-ins don’t necessarily have to be placed into the program directory for Cinema 4D to use them. They can be saved to any path.

Paths to plug-in directories can also be set using the environment variables (see Environment Variables)

How the path list is used can be read here.