The pkg_explorer tool makes use of two categorizations, X-PrimarySection and X-SecondarySection, in order to build a directed cyclic graph of all the packages available in a way that makes it easy to find packages.

The Primary Section represents what is also called the Section. It is a relatively generic category used to group packages such as "Tools" and "Games" together.

We do not impose any naming convention so if you are creating your own environment, you can use anything that makes sense to you.

For additional information, you may want to read more about the Component field.