Examine source code of LMGTFY Add-on

{
  "manifest_version": 2,
  "name": "LMGTFY Extension",
  "version": "1.2.0",
  "description": "Instantly copy links to \"Let Me Google That For You\" for those rudely searchable questions",
  "icons": {
    "48": "icons/lmgtfyaddon-48.png"
  },
  "permissions": [
    "contextMenus",
    "clipboardWrite",
    "notifications",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/lmgtfyaddon-48.png"
    },
    "default_title": "LMGTFY Addon",
    "default_popup": "popup.html"
  }
}