[failoverflow]

It's actually

body { transform: rotateY(180deg); }

[stringham]

Using chrome, and chrome on android inspecting the source shows that it is

  transform: scaleX(-1);

[timothya]

failoverflow was actually right; while scaleX(-1) is present, it's overridden: http://i.imgur.com/mNjGE0F.png

It doesn't matter though, both transforms have the same effect.

[stringham]

On my Chromebook it doesn't override it with rotateY(180deg), but it does on my Linux machine running Chrome 41.