In report view of a list-view, a single list-view item appears similar to a row in a spreadsheet with a number of columns. The first column is the list-view item and the other columns are known as sub-items.
It would be convenient when inserting an item into a list-view to specify all the data for an entire row. This could lead to being able to get all the data for an entire row. This would facilitate moving list-view items from 1 list-view to another, moving items into and from databases, etc..
Each row can conceptually be thought of as the item (first column) and its subitems. A 'full row' object could be composed of a single (required) 'item' object and 0 or more 'subitem' objects.