Examine source code of Hidden Fields Revealer

{
  "manifest_version": 3,
  "name": "Hidden Fields Revealer",
  "version": "0.3.0",
  "description": "Show hidden form fields when activated.",
  "action": {
    "default_title": "Toggle hidden fields",
    "default_icon": {
      "16": "icon-16.png",
      "32": "icon-32.png",
      "48": "icon-48.png",
      "128": "icon-128.png"
    }
  },
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2046724a-0165-4d21-86bf-8f4e7e7104ea}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "css": [
        "styles.css"
      ],
      "all_frames": true,
      "run_at": "document_idle"
    }
  ]
}