Examine source code of Write Better

{
  "name": "Write Better",
  "version": "0.1.1",
  "description": "English grammar suggestions for better writing",
  "manifest_version": 2,
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAg/wAu86aayfkDEvVAGgdtl8FS2/axn1JqdDl9awFDUdSLZrCNJ/7vMJBEUp3IpgzBMF+qFH9UZFQJIuyo2vRHnmIXDMVXEfYLmIJ9WfMYQnu8sUvcTilj7zCzaWSyo1/VqGeahsRX18VZBaMyOc4vauSojZFi66ZkR+dd9JoPhbxFFAMrcZkYeoIL27+ofKRy01gCBN/p3kQtowfvQtxGA+5irSqspXPtFIeTY20ZBhGaYR1KXu9wwa9ghtuQPf00Gy8+FyDzFwemawJ3KjlATokTjqEw9Z8ZM1kB6sS0q50xSJUhlbQ+/FMFN0owm7K5UHTSXGOALS8YPnHASeP3wIDAQAB",
  "permissions": [
    "https://docs.google.com/*",
    "storage"
  ],
  "page_action": {
    "default_icon": {
      "16": "images/quill-orange16.png",
      "24": "images/quill-orange24.png",
      "32": "images/quill-orange32.png"
    },
    "default_title": "Write Better",
    "default_popup": ""
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "https://docs.google.com/*"
      ],
      "include_globs": [
        "https://docs.google.com/document/d/*"
      ],
      "js": [
        "content-script.js"
      ],
      "css": [
        "highlight.css"
      ]
    }
  ],
  "icons": {
    "16": "images/quill-orange16.png",
    "32": "images/quill-orange32.png",
    "48": "images/quill-orange48.png",
    "128": "images/quill-orange128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  }
}