Examine source code of EffCSS Developer Tools

{
  "manifest_version": 3,
  "name": "EffCSS Developer Tools",
  "description": "Extension to inspect EffCSS stylesheets",
  "version": "1.0.0",
  "icons": {
    "16": "icons/on_icon16.png",
    "32": "icons/on_icon32.png",
    "48": "icons/on_icon48.png",
    "128": "icons/on_icon128.png"
  },
  "action": {
    "default_icon": {
      "16": "icons/off_icon16.png",
      "32": "icons/off_icon32.png",
      "48": "icons/off_icon48.png",
      "128": "icons/off_icon128.png"
    }
  },
  "devtools_page": "devtools.html",
  "permissions": [
    "tabs",
    "activeTab",
    "scripting",
    "webNavigation",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "service_worker": "worker.js",
    "scripts": [
      "worker.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "all_frames": true,
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@effcss-devtools.effnd"
    }
  }
}