I've never had lessons, I have no concept of home keys (just had to look up what they are), I type everything without ever looking at my keyboard at a reasonable speed.

I don't use the home keys, I just know where the keys are. I type with my first three fingers and use the pinky for Shift and Ctrl. I can do 120 wpm and am very accurate at it.

When I don't touch-type. I learned touch-typing years ago and use that too when I'm at my ortho keyboard, but I'm much slower and less accurate than my home brew technique.

Isn't this a thing that naturally happens over time? I've never heard of anyone taking typing lessons, even among programmers.

that was my point. the two little lumps on 'f' and 'j' are so you know where to put your pointer fingers in the dark. touch typers feel for them so they can type without looking. It's cool that you can just do that, without knowing, over time.

I don't think this is very unusual for people who spend a lot of time typing.

Yes.