[netbsdusers]

They're not obscure or niche, they are everywhere in operating systems. The linked list is probably the single most essential and the most used data structure in any kernel.

[simonask]

Implementing an operating system is incredibly niche and obscure.

The practices that apply to kernel development do not generally apply to very much else.

[fcantournet]

Ah yes, operating system kernels, famously super mainstream programs that almost everyone works on.