A table and column element is a filter or value field, which does work on/with a specified table and column , eg(e.g. asset.assetType):
Table and column elements are created using the Table and Column tab:
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Everything, except the table and column, which a filter or value field does work on, can be edited using the 3 The Details panel, ie i.e. the choice of table and column cannot be changed after creation.