Plone Modules and file structure. Where do I find modules I want inheritted?

How do you inherit module in plone and where are the Plone Modules stored.?

A classic buildout structure holds all the packaged code in the eggs directory. If you have source checkouts from a vcs - such as git or svn - it is stored in the src or sometimes in a dev-src or extras directory. All this relative to the buildout-directory.

Thanks Jensens.

A little warning: do not edit files in the eggs directory.
If you feel you have to do that, ask a new question and explain what you want to do