<PackageReference Include="System.Configuration.ConfigurationManager" Version="11.0.0-preview.3.26207.106" />

System.Configuration.SettingsDescriptionAttribute

public sealed class SettingsDescriptionAttribute : Attribute
Provides a string that describes an individual configuration property. This class cannot be inherited.
namespace System.Configuration { public sealed class SettingsDescriptionAttribute : Attribute { public string Description { get; } public SettingsDescriptionAttribute(string description); } }