If you click Sync Online without first selecting any licenses (and/or) host IDs, every license in your license database will be included in the sync request, as noted in a confirmation dialog. See below.

Or, you can select one or more entries in the left pane (host IDs or license files) to include only those selected (highlighted) licenses to be included in the sync request.
When you click Yes (if all) or Sync Online for selected licenses, an immediate request is sent to the licensing server. Intermediate popup dialogs may briefly appear while the sync request is handled. The operation concludes with a Synchronization Complete dialog, which summarizes the number of licenses and certificate files that were updated in your Workbench local license database. See below.

If all licenses (and certificates) were already up-to-date, this dialog will say “0 licenses and 0 certificates updated”.
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