OpenWebView2Loader is a reimplementation of WebView2Loader. It is intended to be feature-complete with the original WebView2Loader distributed with the WebView2 NuGet package.
For most intents and purposes, you should prefer using the official WebView2Loader. This implementation may be of interest if you need to understand how WebView2Loader works and could be used to implement WebView2Loader in another programming language without needing a C++ dependency.