  Draco introduced a constraint-based framework to model visualization design
in an extensible and testable form. It provides a way to abstract design
guidelines from theoretical and empirical studies and applies the knowledge in
automated design tools. However, Draco is challenging to use because there is
limited tooling and documentation. In response, we present Draco 2, the
successor with (1) a more flexible visualization specification format, (2) a
comprehensive test suite and documentation, and (3) flexible and convenient
APIs. We designed Draco 2 to be more extensible and easier to integrate into
visualization systems. We demonstrate these advantages and believe that they
make Draco 2 a platform for future research.
