Normally configuration presets depend on the component implementation and are different for each component. There are a few presets however which are often used commonly by different components:
test if set it means that the server runs in a test mode, which may mean different things for different components. The component may use this parameter to turn testing mode on.admins if set it provides a list of administrator IDs. These user may have special access permissions for the component. They usually can execute administrator ad-hoc commands.user-db-uri if set it contains the main database connection string. The component may keep there own data.