Optimizing CSS Delivery in Theme I ran my site through Google PageSpeed Insights and got the following message:

Optimize CSS delivery of the following:

First it lists two CSS files I don't recognize in /sites/default/files

Second, it lists my font awesome css which I'm LINKING to from my .libraries.yml file, like so:

font-awesome:
  remote: https://fortawesome.github.io/Font-Awesome/
  version: 4.5.0
  license:
    name: MIT
    url: https://fortawesome.github.io/Font-Awesome/license/
    gpl-compatible: true
  css:
    theme:
      https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-
awesome.min.css: { type: external, minified: true }
    bootstrap/assets/javascripts/bootstrap/transition.js: {}


So my question then is two-fold:

Short of using another module such as Addvagg

1) How can I speed up delivery of the font awesome css?

2) What are those other CSS files and how can I speed up delivery of them?
download the font &amp; css files, don't use a cdn 
minify and concat your css, additionally you can use sass &amp; gulp to
do the job for you