Epic is composed of a set of modules called plug-ins that are individually installed on your PC. There are one or more plug-ins for each functional area of Epic, plus further plug-ins that provide enhanced functionality such as document export options.
Different plug-ins can be installed on each computer allowing more or less functionality as required (note that users must also have the necessary activities).
Epic can be tailored to your needs via additional plug-ins developed specifically for you (this is where neither Epic's in-built flexibility nor its preferences are sufficient) - a custom plug-in.
You can see a list of all the visible plug-ins installed on your PC either via the 'Plug-ins' menu or the Welcome Screen (see switch visible plug-in). A full list of all plug-ins can be seen be opening the 'About' window (using the 'Help/About Incremental Epic' menu option and then clicking on the 'Plug-in Details' button.