The data feed generated by LogiCommerce is used to supply the databases of portals and search engines. Products generated in that file will be from that moment in the catalog of those portals, so your products will be not only available in your webpage but also in specialized portals.
As each portal demands a file with all the information but in different orders, there is a portal list inside Feed portals so that we generate the feed directly for the wished portal, and the file suits the format and order needed for that portal.