Examine source code of Packs

{
  "manifest_version": 2,
  "name": "Packs",
  "version": "0.2.1",
  "author": "Steven Luke",
  "applications": {
    "gecko": {
      "id": "extension@usepackrat.com",
      "strict_min_version": "57.0"
    }
  },
  "icons": {
    "128": "icon-128.png"
  },
  "background": {
    "scripts": [
      "js/background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "icon-128.png",
    "default_title": "Packs",
    "default_popup": "popup.html"
  },
  "permissions": [
    "<all_urls>",
    "activeTab",
    "https://packs.co/*",
    "contextMenus",
    "storage"
  ],
  "web_accessible_resources": [
    "popup.html",
    "embedded.html"
  ]
}