<PackageReference Include="Microsoft.Identity.Client" Version="4.83.3" />

Microsoft.Identity.Client.OAuth2.OAuth2AssertionType

static class OAuth2AssertionType
public const string JwtBearer = "urn:ietf:params:oauth:client-assertion-type:jwt-bearer"

public const string JwtPop = "urn:ietf:params:oauth:client-assertion-type:jwt-pop"