Where is ustore_stub_io.c?

The pdf "Embedded MotionApps Platform Release User Guide v2-0" states on pdf page 12 (doc page "11 of 26") under section 4.8:

"A stub Ustore IO layer with comments describing implementation recommendations is provided in ustore_stub_io.c. Please see the Embedded MotionApps Platform Functional Specification for more information."

But unfortunately, ustore_stub_io.c is nowhere to be found...

Anyway to get access to this file?

Thanks.