aqua - Include support for the Mac OS X Aqua (Carbon/Cocoa) GUI
debug - Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
doc - Add extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
handbook - Enable handbooks generation for packages by KDE
minimal - Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
