This is a sport of Golden Delicious, and very like.
But as you can see, these don't really look much like the Golden Delicious you'll find year-round in your supermarket. This one has a distinct blush, for goodness sakes, rosy orange over skin that is more green than yellow. There's some russet and fly speck too. The lenticels are dark green, light green in the blush.
True, it is conical, tapered, and ribbed, like the G Delish we all know--but so are many varieties.
In any case, Golden Delicious deserves a repeat performance.
The flesh is crisp, juicy, and on the coarser side of fine-grained, a light creamy yellow. The flavor is unquestionably Golden D, sweet, mild, and rich, with honeyed pear and a whiff of something generically vegetable.
Golden Delicious keeps well, and is widely available, but is worth sampling direct from the orchard once in a while. (Mine was fresh at the end of September.)
Sports like Smoothee are natural mutations with some valuable trait that makes them worth keeping. Often these traits are invisible to the consumer, in that they do not look or taste or keep better, but are better yielding or disease or temperature resistant or otherwise hardier, or easier to care for or harvest.
All About Apples has a page of sports of popular varieties; Smoothee is listed as "Smoothee Improved Golden Delicious."
According to Geraldine Warner, "Smoothee" is the trademark for this variety, and although the patent on Smoothee has expired, the trademark has not! So growers may propagate this sport legally, without paying a license fee, if they call it something else, and the accepted generic name seems to be "Improved Golden Delicious."