What are product feeds in general?
A Product Feed is a collection of links contained in a single file. However links alone will not be of much use to most Publishers. So the more information that can be provided that is relevant to each link, the more options are available for a Publisher to sort, filter and display those links.
For example, a general retailer may have a feed containing their entire stock inventory, containing part numbers, descriptions, colours, prices and so on. A Publisher can use this feed to quickly find or display the links they require, instead of searching the retailer’s site manually.