This.
Indexing is So. Damn. Important.
Documentation and knowledge discovery is crucial, and still very much a WIP.
I don't claim to have the answer. I write a lot of really relevant, heavy-duty documentation, with my projects.
That no one reads.
I know this, because they keep asking me questions that are in the docs.
I am their index.
My stuff isn't particularly popular, so it doesn't take much of my bandwidth (well, actually, one project is very popular, but that has been taken over by a fairly energetic and talented team).
When this happens, it’s tough to say what’s worse - a stale, and sometimes wrong document, or no document at all. So, in my career I’ve come to rely less and less on docs, and more and more on just reading the code. Docs can lie - code rarely does.
It does require a teensy bit of extra discipline and vigilance, on my part, but it is usually supported by many tools.
If I do it that way, it's automatically displayed in mouseovers in Xcode, and can be compiled into organized sites, by Jazzy.
I write about my methodology, here: https://littlegreenviper.com/miscellany/leaving-a-legacy/