The last set of interfaces implemented by the TSF manager are the 'odd-ball' interfaces that don't really fall into any other logical groups.
The interfaces in this category provide auxiliary services for applications or text services.
How to Obtain
QI on ITextStoreACPSink
Passed to ITextStoreACP::AdviseSink
Passed to ITfTextEditSink::OnEndEdit
These interfaces were originally created to allow TSF to interoperate with MSAA. Unfortunately, no 3rd party developers implemented the MSAA client support needed to make these interfaces work, so at this point, these interfaces are effectively obsolete.