My read of `config.js` is that the lines of the form `exports: "_"` mean that the symbols we use are defined on a global scale.  Am I wrong?  If not, it is redundant to declare the bindings in the individual `js` files (and we make some inconsistencies, e.g. in `Backbone` being variously `backbone` or `Backbone`) -- so we are better off simply declaring them here as imports which get the standard export/binding name.  Of course if I'm wrong I'm happy to revert!