#Linux base image -> filesystem layers -> #Docker image.
And this for every OS. Not just Linux.
#Windows and #macOS developers must have Docker sit on top of a mini Linux #VM to run the GNU/Linux toolset of anything they are working on.
Think about it. Any library, #interpreter, compiler the community laboriously made available to run #natively on your platform of choice is now useless. Because Docker runs on every platform. But in reality it executes only on top of Linux.