What is Cube obj made of?

[Nurech]

I would like to use your solver to solve an external cube state and return an solve.

1. Please explain what is Cube obj made of so I know how to map my external cube to this obj.

{ "center": [],
    "cp": [],
    "co": [],
    "ep": [],
    "eo": [] }

cp = corner pieces?
ep = edge pieces?
etc.

2. Does during solve() Cube at anytime flip axis?

3. Is is possible to validate if passed string to make new Cube is a valid string?

Thank you!