Examine source code of Tab Auto Refresh

{
  "manifest_version": 2,
  "name": "Tab Auto Refresh",
  "version": "1.0",
  "description": "Tab Auto Refresh is a Firefox addon that helps you automatically reload tabs of your choice.",
  "permissions": [
    "activeTab",
    "storage",
    "tabs",
    "notifications",
    "alarms",
    "<all_urls>",
    "declarativeNetRequestWithHostAccess"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "icons": {
    "48": "icon.png",
    "128": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4ceb67de-792c-462a-912f-52a2a69712e2}"
    }
  }
}