[css-2d-transforms] Section on "Recomposing the matrix" doesn't make much sense

In section 7.4 of the current 2d transforms editor's draft (no public 
version of this, so no link, sorry), there is a bunch of text that seems 
to be defining what to do in terms of 3d transforms.  Or so I assume. 
It doesn't actually say what the notation it's using means.

In any case, I suspect that using the first Euler angle to rotate in all 
three directions is just wrong.

-Boris