<PackageReference Include="Microsoft.Extensions.Configuration" Version="10.0.0-preview.2.25163.2" />

ConfigurationManager

public sealed class ConfigurationManager : IConfigurationManager, IConfiguration, IConfigurationBuilder, IConfigurationRoot, IDisposable
Represents a mutable configuration object.
public string this[string key] { get; set; }

public IList<IConfigurationSource> Sources { get; }

public ConfigurationManager()

Creates an empty mutable configuration object that is both an IConfigurationBuilder and an IConfigurationRoot.

public void Dispose()

public IEnumerable<IConfigurationSection> GetChildren()

public IConfigurationSection GetSection(string key)