Somewhere on the interwebz there has to be a general purpose tutorial on how to use peaking.

All the ones give basic information and then 'here are other options you can change' but with no information on what they do and why you would want to use it.

I've searched on threads here asking how to use peaking and zebras and the only answer was about zebras.

Dunno why but I just find it baffling. Dunno if it has to do with my particular quality of poor eyesight but I just can't see what I'm supposed to be seeing!

On which camera? Peaking doesn't work equally well on all camera's, sometimes it can be a bit misleading and you better magnify the screen to double check.

Well, that is my point. There are plenty of camera specific tutorials on youtube.

I'm looking for general knowledge: I want to know how to use ->peaking<-in a general sense so that I can determine the best settings. I assume that they all have the same settings even if they call them different things.

My only camera right now is an ancient but still functional HV20 (which is just has peaking on-off). But when I had the Canon T4i, Magic Lantern gave you all kinds of settings. (T4i was not a really good choice for video--even with Magic Lantern.)

There is not much to say about peaking really, most camera's let you use different color and it highlights the edges of what is in focus, if it's not highlighted it's out of focus, if it is it's in focus, that's all there is to it, teh biggest difference is that some camera have quite thick peaking lines making it more difficult to judge and sometimes they are not even very accurate, the jvc gy ls300 as an example, eventhough the viewfinder and lcd are not high rez screens, has very accurate peaking and make it easy to nail focus.