I'm using a WebView like this
<WebView Source="{Binding Url}"/>
viewModel.Url = "https://google.com/[]"
and on android it shows an ERR_FILE_NOT_FOUND message
Xamarin supported square brackets in URLs, but Maui does not. Replace them with their percent encoding.
viewModel.Url = "https://google.com/[]".Replace("[", "%5B").Replace("]", "%5D");
the page will then correctly load (as google's 404 page :P). As far as I can tell square brackets aren't universally supported anyway