Examine source code of Environment Switch

{
  "description": "Helps you to switch between your server environments (local, development, test and live!)",
  "manifest_version": 2,
  "name": "Environment Switch",
  "version": "1.0",
  "homepage_url": "https://blog.senthilprabu.in/portfolio/environment-switch",
  "icons": {
    "48": "icons/logo.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/logo.png",
    "default_title": "Environment Switch",
    "default_popup": "popup/environment_switch.html"
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "commands": {
    "local": {
      "suggested_key": {
        "default": "Alt+1"
      },
      "description": "Switch to local environment"
    },
    "development": {
      "suggested_key": {
        "default": "Alt+2"
      },
      "description": "Switch to development environment"
    },
    "test": {
      "suggested_key": {
        "default": "Alt+3"
      },
      "description": "Switch to test environment"
    },
    "production": {
      "suggested_key": {
        "default": "Alt+4"
      },
      "description": "Switch to production environment"
    }
  }
}