<PackageReference Include="System.Security.Permissions" Version="10.0.0-preview.1.25080.5" />

SecurityZone

public enum SecurityZone
Defines the integer values corresponding to security zones used by security policy.
namespace System.Security { public enum SecurityZone { Internet = 3, Intranet = 1, MyComputer = 0, NoZone = -1, Trusted = 2, Untrusted = 4 } }