it uses the canvas replacement hack, which allows you to use a fragment shader as a post-processing step
i don't see why not; i assume ayo didn't include it in borksy just cause it's one of the more technically complex hacks (you have to be able to write GLSL), but there's no harm in asking him to add it!
you can always use the additional JS field in borksy to include hacks that aren't natively supported in the meantime