Examine source code of Character Count

{
  "manifest_version": 3,
  "name": "Character Count",
  "description": "Count characters and words in text",
  "version": "1.1.0",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{c9d8e7f2-3b4a-4f5e-9a1b-2c3d4e5f6789}",
      "strict_min_version": "109.0"
    }
  }
}