(Her actually.) It's M+ 1mn Light (M+ fonts, Type 1, monospace). I think the whole family is attractive & readable and for programming on OS X I wanted something with a lighter font weight (it's got 5) to compensate for OS X's overly heavy rendering of light text on dark backgrounds. For Linux/BSD terms I tend to use either the medium weight or use monofur.
You're welcome. I never think of it as an obscure font family so I didn't list it, but I guess it's not so well known. I can see what you mean about high-dpi though Regular is still a bit too heavy for my tastes, I've just spent too many years on linux terminals that render light-on-dark much lighter. I run at 12-14pt in iTerm2 on a low res 13" mbp, so that may make a big difference as well.