<PackageReference Include="System.Configuration.ConfigurationManager" Version="10.0.0-preview.7.25380.108" />

System.Configuration.SettingElement

public sealed class SettingElement : ConfigurationElement
Represents a simplified configuration element used for updating elements in the configuration. This class cannot be inherited.
namespace System.Configuration { public sealed class SettingElement : ConfigurationElement { public string Name { get; set; } public SettingsSerializeAs SerializeAs { get; set; } public SettingValueElement Value { get; set; } public SettingElement(); public SettingElement(string name, SettingsSerializeAs serializeAs); } }