Examine source code of Tab Customizer

{
  "manifest_version": 3,
  "name": "Tab Customizer",
  "version": "1.0",
  "description": "Customize Firefox tabs and manually unload them.",
  "permissions": [
    "menus",
    "tabs",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon.png",
      "48": "icon.png",
      "128": "icon.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-customizer@versionOne",
      "strict_min_version": "109.0"
    }
  }
}