headman lists and validates all the components of your project. For maximum convenience, you can define json test data which can be reused from other components. This allows you to work independently from a backend. headman uses consolidate.js internally, hence it automatically supports a lot of rendering engines.
You can define variations for each of your components. These variations inherit data from the components base definition (if defined), which can then easily be overwritten or extended.
If you have a component that includes another component, you can easily include the data (or one of its variations) of the latter into the data of including component. That way, it is enough to define data for a specific component once.