Examine source code of AnGRR Countdown Addon

{
  "manifest_version": 2,
  "name": "Countdown Addon",
  "version": "1.0",
  "description": "Countdown in Sidebar.",
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_title": "Sidebar öffnen/schließen",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    },
    "default_popup": "popup.html"
  },
  "sidebar_action": {
    "default_panel": "sidebar.html",
    "default_title": "Countdown Sidebar"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{79f88483-602d-4926-a188-128ff9fca1c7}"
    }
  }
}