Hi @nickjj ,
we are using flask-webpack, thanks for creating it!.
We have an entry in our webpack.config.js that points to a js file, i.e.:

        customers: [
            rootAssetPath + '/src/client/apps/customers.js'
        ],

which, at some point, requires some stylesheets, i.e.

require('../styles/customer/main.scss');

var app = angular.module('app', [
    'ngRoute',
    'ngResource',
    'ui.bootstrap',
    'ui.mask'
]);

The resulting build contains a js file which we include in one of our pages using javascript_tag and a css file which we also want to include in that page. The css file is built correctly but it does not show in the resulting manifest.json file, so we made this format. I'm pretty sure this does not need to be included in your package but I thought I would submit the PR just in case. Maybe you have a suggestion of how we could do this without the custom format.

Again, thanks for this and for the awesome video you made explaining how it all fits together.