I don't have my device in front of me but in the menu is an item dealing with application catalogs. It should provide a list of places where apps are pulled from. There should be an item for extras-devel (and hopefully one for extras). If there is not one for extras, just delete "-devel" and hit ok. If there is an "extras" one, go into the editor for "extras-devel" and I think there is a check box to disable it.