[U15] CONNECT EDITION MS_DGNLIBLIST_ITEMTYPES

I am experiencing a fault in opening files with this new variable set.
Can anyone please explain how it is to be used?

The documentation provides only rudimentary information, and no examples, that if followed as per other variables, causes a fail to open.

There was a post on the Insiders forum, about 2 new "required" variables for ITEMTYPES, but no further progress has occurred there, so posting here.

MS_DGNLIBLIST_ITEMTYPES
DGN Library Itemtypes List
List of DGN library files that are used to find available ItemTypes for your current session.

If I set to the same as "MS_DGNLIBLIST", i.e.

MS_DGNLIBLIST_ITEMTYPES =  $(_USTN_WORKSPACESTANDARDS)DgnLib/*.dgnlib

Microstation will fail to open files, and after a time attempting to open the DGNLIB, brings up the Abort, Retry, Ignore dialogue.