Examine source code of Environment Warning

{
  "name": "Environment Warning",
  "manifest_version": 3,
  "incognito": "spanning",
  "optional_permissions": [
    "scripting"
  ],
  "permissions": [
    "storage",
    "tabs",
    "contextMenus"
  ],
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "version": "0.1.0",
  "description": "Extension to assist development by warning you about the environment you are currently on.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "host_permissions": [
    "*://*/*"
  ],
  "action": {
    "default_icon": {
      "16": "icon16.png",
      "32": "icon32.png",
      "48": "icon48.png",
      "128": "icon128.png"
    },
    "default_area": "navbar"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "environment-warning@arjanfrans.com"
    }
  }
}