Gives you access to a virtualised ARM based Raspberry Pi machine running the Raspian operating system. This is not just a Raspian Docker image, it’s a full ARM based Raspberry Pi virtual machine environment.
How it does its thing:
A full ARM environment is created by using Docker to bootstrap a QEMU virtual machine. The Docker QEMU process virtualises a machine with a single core ARM11 CPU and 256MB RAM, just like the Raspberry Pi. The official Raspbian image is mounted and booted along with a modified QEMU compatible kernel.