Since version 4.0, GeoBlazor uses a code generator to create the wrapper around types in the ArcGIS Maps SDK for JavaScript. While we strive to test thoroughly all generated code, sometimes inter-dependent types require us to expose them before they are fully tested. The Experimental “GeoBlazor_Untested” warning is used to mark these types. We will remove this warning once we have tested the code and are confident it works in a future release. In the meantime, you may suppress the warning with #pragma warning disable GeoBlazor_Untested in your code, or using <NoWarn>GeoBlazor_Untested</NoWarn> in your project file.