How is canned corned beef made?
what gives canned corned beef its flavor


Consider the flavor of canned corned beef as similar to freshly cooked brined corned beef, with these exceptions:


The canning process requires product in the can be heated under pressure to 250+ F, this high temperature will change flavor notes and texture.
Food labeling standards allow 10% of canned corned beef to be a flavored solution. This will have a large impact on flavor. This will generally be a proprietary trade secret.
Canned Corned Beef will most likely be made from lower quality cuts of meat (ie. the one not good enough to be sold as fresh corned beef brisket). This lower quality cut will have a different flavor. Probably fattier.



  there is very little information on the canning process of canned corned beef 


I just Googled, you're right, very little info. I do not home can, so I can't provide a lengthy answer. I found a historical recipe here, 
Ball Blue Book of Canning and Preserving Recipes:



Note: That recipe will not provide you with something similar to commercially canned corned beef. It will be a jarred liquid and chunks, it might be better than canned.

For information on commercial canning, Google the term: corned beef retort. A retort is what commercial canners use to sterilize canned products.