Examine source code of PixelPerfect Pro

{
  "manifest_version": 3,
  "name": "PixelPerfect Pro",
  "version": "1.0",
  "description": "Overlay design mockups on live websites for pixel-perfect comparisons",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_icon": {
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    },
    "default_title": "PixelPerfect Pro",
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_scripts/overlay.js"
      ],
      "css": [
        "content_scripts/overlay.css"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "images/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "pixelperfectpro@designtools.com"
    }
  }
}