@gnarf - I just did a ilttle test, add ```console.log('hi manifest_helper')``` in ```manifest_helper'``` and we get 3 times. So I prefer remove one of them. 

btw: If you want to use lazyload, please follow the rule.
```JS
<!--
<script defer src="shared/js/keyboard_helper.js"></script>
-->
```
https://github.com/mozilla-b2g/gaia/blob/master/apps/system/index.html#L25