In many cases, what I find lacking is not "unannotated class list" Doxygen documentation, or contextual examples, but proper documentation of pointer lifetimes,

In many cases, what I find lacking is not "unannotated class list" Doxygen documentation, or contextual examples, but proper documentation of pointer lifetimes, and invariants (for example the `snd_pcm_link` docs merely say the two streams will start and stop together, but doesn't say it fails unless you're linking two hardware devices with a shared underlying clock which will are supposed to remain in sync indefinitely), and for new project contributors, architectural/implementation and control flow documentation. Unfortunately invariants often live in the original programmer's head more than the code, pointer lifetimes are often nonlocal in the codebase, and architecture/implementation and control flow is inevitably nonlocal, requiring weeks or months of efforts for a motivated non-author to learn, far beyond the patience of someone fishing for Hacktoberfest T-shirts.