Looks like you're right, I just saw it in the Windows SDK winnt.h file, it's defined as:

#define CREATE_BOUNDARY_DESCRIPTOR_ADD_APPCONTAINER_SID 0x1

I'm not sure on which line to add it to, is it okay to add it on line 3750, before��#define SID_REVISION?

How come they used the value 0x1? It's 0x01 on the Microsoft Docs site. As far as I know, they are the same value but differ in bit value and the compiler evaluates��them to the same value. So for copyright purposes, would it be better to add or remove extra 0s? Should I do the same for��PRIVATE_NAMESPACE_FLAG_DESTROY?