Examine source code of Base64 Pal

{
  "manifest_version": 3,
  "name": "Base64 Pal",
  "version": "2.0",
  "description": "Decode Base64 text inline on web pages — right-click to decode selected text, decode all on page, or undo.",
  "permissions": [
    "contextMenus",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "base64-pal.mrx@gmail.com",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "service_worker": "background.js",
    "scripts": [
      "background.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "commands": {
    "decode-selection": {
      "suggested_key": {
        "default": "Alt+Shift+D",
        "mac": "Alt+Shift+D"
      },
      "description": "Decode selected Base64 text"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "24": "icons/icon24.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "128": "icons/icon128.png"
  }
}