Examine source code of Tab Auto-Closer

{
  "manifest_version": 2,
  "name": "Tab Auto-Closer",
  "version": "1.2.0",
  "description": "Automatically closes tabs after a customizable time period",
  "homepage_url": "https://github.com/johhansantana/firefox-tab-auto-closer",
  "permissions": [
    "tabs",
    "storage",
    "menus",
    "contextMenus"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Tab Auto-Closer",
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1812e727-c659-4656-92cb-a043a5b2f74f}"
    }
  }
}