I think the "Ugli Tomato" is a marketing ploy much like the "grape" tomato, which started with the cultivar "Santa". I only find reference to it at specialty grocers, If you find one, try to find out where it was grown, and the name of the packer, We may be able to backtrack from there and find the cultivar name. Many of the fancy tomatoes are imported from countries where growers are quite secretive so it may remain a mystery for awhile....."
I think you are being unfair to the growers. I know of NO commercial grower who saves his own seed, but there are many commercial varieties not on sale to the "Amateur market". See Tomatoes in this link
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might find some Packer who has decided to put his own "Brand" on a product.
Over here in the UK there is a move to describe small/under size apples as "child size". In the past when apples were sold "Jumble packed" that is loose in boxes you just picked out the size that suited your family best,