Most of the logic and configuration modules are contained in keplerjs:core under the Kepler namespace Kepler. or K. is the same thing. Inside this namespace the general rule is that Modules or Models are capitalized instead the configuration objects are lowercase.
The views that define the base User Interface structure of Kepler are contained in keplerjs:core-ui. This also contains the helpers templates used by all views and the minimum CSS essential for the behavior of the UI.