Where did you even find it? The compensation page has a section heading for it but I couldn't find an actual calculator anywhere, just a big formula.
If you scroll down about 2/3 of the way, you'll see it.
It's not competitive for me at all. I'm right beside Vancouver (Canada) where living costs are about 95% the same as Vancouver, but if I enter that, It says my salary range would be considerably less than I earn now. This seems like a really cool opportunity and I want to apply, but my family can't afford the hit (I'm the only source of income we've got and this place is crazy expensive). Kind of a bummer - it's hard to find jobs doing cool things and also earning decent money.