Examine source code of Dev Environment Switcher

{
  "manifest_version": 2,
  "name": "Dev Environment Switcher",
  "version": "1.0",
  "description": "Quickly switch between dev, staging, and prod domains.",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png",
    "default_title": "Switch Environment"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{62ea8fee-262a-46e9-9107-3cf74875c7e8}"
    }
  }
}