Examine source code of CSS Debug Overlay Plus

{
  "manifest_version": 2,
  "name": "CSS Debug Overlay Plus",
  "version": "1.3",
  "description": "Enhanced visual CSS debugger with responsive, contrast, and performance tools.",
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "contextMenus"
  ],
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_title": "CSS Debug Overlay Plus",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "overlay.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{82ca305e-920a-432b-ad80-a4c4a7bfa080}"
    }
  }
}