I thought Docker is a common standard that defines. How archive format? How build file format? How the config format? What operation system need to support in o

I thought Docker is a common standard that defines. How archive format? How build file format? How the config format? What operation system need to support in order to be fully compatible with docker cli? Instead of a cli tool. Because there are already standalone docker implementations that implemented with completely different technology. Just like docker on windows (the one runs exe).