How do OneDrive's "smart files" work?

Since Windows 8.1, OneDrive uses "smart files" to represent files that exist in the cloud but are not available locally. How does this feature work? I can't find any documentation about it.

I can see that files that are not available offline have the following attributes:

Hidden, System, Archive, SparseFile, ReparsePoint, Offline

Also, using fsutil, I discovered that the reparse tag value is 0x80000015, which is not one of the IO_REPARSE_TAG_* values listed in WinNT.h. (EDIT: actually it is: IO_REPARSE_TAG_FILE_PLACEHOLDER; I was looking at the WinNT.h from Windows 7 SDK, and this value is new in Windows 8.1)

But that's about the only thing I could discover about them...

Is it possible to use this feature in my own app (i.e. provide my own smart files)? What APIs are available to manipulate those files?