<PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="5.0.0-preview.1.20120.4" />

IConfigurationBuilder

public interface IConfigurationBuilder
Represents a type used to build application configuration.
IDictionary<string, object> Properties { get; }

Gets a key/value collection that can be used to share data between the IConfigurationBuilder and the registered IConfigurationSources.

IList<IConfigurationSource> Sources { get; }

Gets the sources used to obtain configuration values

IConfigurationBuilder Add(IConfigurationSource source)

Adds a new configuration source.

IConfigurationRoot Build()

Builds an IConfiguration with keys and values from the set of sources registered in Sources.