<PackageReference Include="Microsoft.Identity.Client" Version="4.90.0" />

Microsoft.Identity.Client.AppConfig.PoPOptions

public class PoPOptions
Options that control mTLS Proof-of-Possession (PoP) token acquisition. This type is the extensibility point for PoP-related knobs so future settings can be added without growing the builder surface.
namespace Microsoft.Identity.Client.AuthScheme.PoP { public interface IPoPCryptoProvider { string CannonicalPublicKeyJwk { get; } string CryptographicAlgorithm { get; } byte[] Sign(byte[] data); } }