It is impossible to export directly Variables data, as because it is complex data. In order to get variables for the item, a few tables should be exported and merged using instruments of Tableau Desktop
As an example, variables for Catalog Tasks will be extracted below.
Variables are not directly connected to the tasks. They are connected through the requested_item field from the Options table. Use Tableau Connector to export data from the tables:
And then, use Tableau Desktop Edit Relationship to join table fields and get the results:
NOTE: Take a look at the visible explanation of how Variables connected to data through the tables