RtlIsPackageSid

UINT8 __fastcall RtlIsPackageSid(VOID *Sid){
  return *((_BYTE *)Sid + 1) >= 2u
      && *(_BYTE *)Sid == 1
      && RtlCompareMemory((char *)Sid + 2, (VOID *)&RtlpAppPackageAuthority, 6ui64) == 6
      && *((_DWORD *)Sid + 2) == 2;
}

Referenced by:

NtCreateLowBoxToken
ObpVerifyAccessToBoundaryEntry
SepFilterToken