Examine source code of Check updates

{
  "description": "At the start of your session or when you click on check, it will verify if some text that you want to monitor on specific website have changed. Changes will be visible on the manage page. To add new text to monitor right click on it (or select it then right clic) and \"Add to check\"",
  "manifest_version": 2,
  "name": "Check updates",
  "version": "1.2.5",
  "icons": {
    "48": "icons/something.png"
  },
  "browser_action": {
    "default_icon": "icons/something.png",
    "default_title": "Check Updates",
    "default_popup": "/popup/popup.html"
  },
  "permissions": [
    "tabs",
    "http://*/",
    "https://*/",
    "storage",
    "contextMenus",
    "menus",
    "alarms"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "addon@check.com"
    }
  }
}