When you open a wikipedia.org page, this extension inserts a small little button (X) into each row of sortable tables. When you click the X, All rows in all tables will disappear that contain the same text as in their first cell as the row you clicked the X in. This makes getting rid of rows you're not interested in very easy.
The extension also inserts a table at the end of the page in which you can find all the rows you deleted. You can restore any removed rows by clicking the X by their names.