Examine source code of Only Good Domains

{
  "manifest_version": 2,
  "name": "Only Good Domains",
  "description": "Create blocklists from domains collected while browsing the web. Whitelist good, judge unknown, blacklist and block bad domains.",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "version": "1.1.2",
  "permissions": [
    "<all_urls>",
    "webRequest",
    "webRequestBlocking",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon-16.png"
    },
    "default_popup": "popup/popup.html"
  }
}