There's webview (https://github.com/webview/webview https://github.com/webview/webview) which has bindings for many different languages, but it's a whole window

There's webview (https://github.com/webview/webview https://github.com/webview/webview) which has bindings for many different languages, but it's a whole window rather than a UI component you can embed. It's intended to be a lightweight alternative to Electron.