I think the Laravel developers don’t know what a Pivot Table is. At the time of writing:

If you need to define attributes that should be set on the pivot / intermediate table linking the models, you may use the hasAttached method. This method accepts an array of pivot table attribute names and values as its second argument

The concept they’re looking for is Association Table.
Oh, look. I just noticed this on the Wikipedia article: “pivot table (as used incorrectly in Laravel – not to be confused with the correct use of pivot table in spreadsheets)”; so this has already been discovered.