Examine source code of alt+shift

{
  "name": "alt+shift",
  "version": "1.0.1",
  "manifest_version": 2,
  "description": "alt+shift extension for when you forget to press alt+shift",
  "permissions": [
    "scripting"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://www.google.com/*",
        "*://www.bing.com/*"
      ],
      "js": [
        "background.js"
      ]
    }
  ],
  "icons": {
    "16": "icon/icon16.png",
    "32": "icon/icon32.png",
    "48": "icon/icon48.png",
    "128": "icon/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1ca2d5eb-048e-49cf-8059-94c5be8b2c0a}"
    }
  }
}