The term used on the websites is a laquer finish.
Notice that when you read the data sheets, the items listed are approved for use as coatings on paper containers and as the gasket on cans. Not the lining on the can, just the gasket area where the lid is seamed onto the can.
The pallets and boxes were labelled "enamel" and we had to make certain that the lids and cans were of the same coating. I also had to work with the quality control department to make sure that the stamped codes on the cans were not cutting through or cracking the coating on the inside of the lids.
http://www.steeluniversity.org/content/html/eng/default.asp?catid#5 &pag eid 81272441
This is the application of an organic coating to create a barrier between the steel and its contents (filling) and the external environment (atmosphere). The flexibility of the exterior coating depends on the type of can or component being manufactured. The interior coating depends on the kind of product and processing environment. This will influence the thickness of the coating too. Tinplate food and beverage cans are internally lacquered to prevent chemical action between the filling and the can wall and to prevent metal dissolution into the filling. For dry contents (interior) and the exterior of cans, tinplate provides sufficient protection and does not need lacquering. For white fruits and sometimes tomato based fillings the can walls are unlacquered to allow low level tin dissolution which preserves the original color of the filling.
http://www.cancentral.com/hist_timeline.cfm 1921 Zinc oxide and other zinc compounds in an enamel lining were found to prevent discoloration of canned corn by "corn black" or zinc sulphide.