It seems that since windows 10 ntdll has security feature called "ProtectedPolicies" - you can query it with 
RtlQueryProtectedPolicy function. Prototype of this function is:
NTAPI NTSTATUS RtlQueryProtectedPolicy(GUID *, PDWORD out_flag);
Lets see how it works:
loc_6A277EFB:   ; CODE XREF: RtlQueryProtectedPolicy(x,x)+12 j
  push    edi
  mov     edi, offset _RtlpProtectedPoliciesSRWLock
  push    edi
  call    _RtlAcquireSRWLockShared@4    ; RtlAcquireSRWLockShared(x)
  push    offset _RtlpSearchProtectedPolicyEntry ; PtFuncCompare
  push    14h                           ; SizeOfElements
  push    ds:_RtlpProtectedPoliciesActiveCount ; NumOfElements
  push    ds:_RtlpProtectedPolicies     ; Base
  push    [ebp+Key]                     ; Key
  call    _bsearch
That policies stored in array 
RtlpProtectedPolicies, count located in 
RtlpProtectedPoliciesActiveCount and size of each policy is 0x14 bytes (0x18 under x64), so each policy looks like struct:
struct protected_policy
{
  IID guid;
  DWORD flag;
};
Lets see from where 
RtlQueryProtectedPolicy called