<PackageReference Include="Newtonsoft.Json" Version="13.0.4" />

System.Diagnostics.CodeAnalysis.FeatureSwitchDefinitionAttribute

Indicates that the specified public static boolean get-only property corresponds to the feature switch specified by name.
namespace System.Diagnostics.CodeAnalysis { internal sealed class FeatureSwitchDefinitionAttribute : Attribute { public string SwitchName { get; } public FeatureSwitchDefinitionAttribute(string switchName); } }