(I've been working on OpenGL platform translation for years)

Reconstructing quads from pairs of triangles is just about doable in a one-liner. The harder part in my opinion is applying texture mapping to the resulting triangle, but it's not unreasonably difficult.

    // this depends on your winding
    triangles = [1, 2, 4, 2, 3, 4]
    quads = []
    for i in xrange(len(triangles), 6):
        t = triangles[i:i+6]
        quads += [t[0], t[1], t[4], t[2]]

The only things I think are interesting here are their heuristics on shaders to apply color maps, and the fact they shipped a game with it.

No, you're right, there's no quad reconstruction. I imagine you could have just used quads in both the WebGL and Canvas renderers to achieve a similar effect.