epp works in three places:

The Python module epp which is a common Python package and can be ignored, once installed.

An install wizard lets you choose a global epp folder which stores custom settings, templates, standins etc. To be able to find the location from the python module is stored in a system wide EPP_ROOT environment variable. Here the default structure:

Contains

config.xml Global configuration file templates

images

standing.png: Template image that is used for shots

header.png: Header for epp gui

project_dirs

Project.xml

shot_dirs

Shot.xml

formats.xml

The install wizard lets you also define the project root folder. This is the folder where you keep all your project assets, data etc., your working directory for Fusion Comps, Generation, 3D apps etc.

The add_project and add_shot guis will create directories inside this folder.