The issue jQuery came across was the use of `//@`, which is required for source maps, being confused as `//@cc_on` and sometimes throwing in IE. The solution was to wrap the source map pragma comment in a multiline comment block e.g.

```js
/*
//@ sourceMappingURL=...
*/
```

That's why I added it to the `*.prefix` files. But it can easily just be appended to the bottom like you've done here.