How about “any random person with a computer”? 
No, but seriously… I think a key success for open source is that anybody can get started with it. I’m just a case in point, I have a ph.d. in informatics, but I got there from being autodidact. My father got a PC in the house in 1985, I started out looking at BASIC code as a kid, and when the Web came around, it was “View Source”. I did write code as a teenager with extremely little training, and just a few courses as part of my master’s in theoretical astrophysics.
Apart from that, it has just been looking at other people’s code, RTFMing and eventually working with better coders than myself. And yet, here I am. I would hate to see the bar sat any higher, I think humanity would be poorer for it.