I think this is a bug. I set the ig.lib from 'lib/' to 'js/'. But the debug loads a css file via ig.prefix... this doesn't make sense.

So instead of:
style.href = ig.prefix + 'lib/impact/debug/debug.css';

I changed it to:
style.href = ig.lib + 'impact/debug/debug.css';

This is what it should be, shouldn't it?