This command is a special debug version of Reprocess and is not used in normal operation.
Compared to Reprocess, it does not mark BI assets for the update with Force on Demand Pull, but rather handles them in another way and in foreground.
With Reprocess Ext, the up-to-date data from the selected BI assets is fetched from Tableau and stored to a special table of MMDB which is not accessed via MMTE Client interface.
You will not see the effect of this command in UI. Normally, Infolytik technical support executes this command and/or uses its results.