[$] Finding real-world kernel subsystems

The kernel development community talks often about subsystems and subsystemmaintainers, but it is less than entirely clear about what a "subsystem" is inthe first place. People wanting to understand how kernel development workscould benefit from a clearer idea of what actually comprises a subsystemwithin the kernel. In an attempt to better understand how kerneldevelopment works, Pia Eichinger and her colleagues spent a lot of time lookingfor the actual boundaries; Eichinger presented that work at the 2021linux.conf.au online gathering.