Examine source code of Viewport & Tailwind CSS Container Inspector

{
  "manifest_version": 3,
  "name": "Viewport & Tailwind CSS Container Inspector",
  "version": "1.0.1",
  "description": "Shows the viewport width in px and rem, plus if Tailwind CSS is discovered on the page it will show the matching Tailwind container breakpoint, in a small overlay. You can change the settings for a few different themes and positioning and can also be enabled/disabled.",
  "browser_specific_settings": {
    "gecko": {
      "id": "viewport-tailwind-size-inspector@evomark.co.uk",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Viewport & Tailwind Size Inspector",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "all_frames": false,
      "run_at": "document_start"
    }
  ]
}