What the article is referring to is the plate,
located between the brisket and flank:
It is the 'sparerib/belly' section of the steer, same as on the pig. Off the top of the plate is the skirt steak, just like what you trim off a sparerib. Then you take the ribs off (the sparerib) and what's left is the belly (just like pork belly, except beef belly). Same thing, just different animal.
My dad would make beef belly bacon for Jewish families in the area who could not eat pork. It was quite good, but rather tallowy - very dense fat. We'd also slice up the belly fresh (sidebeef) and cured (cornedbelly) too prior to smoking. I'd take a couple slices upstairs (we lived over the store) and fry them up for lunch on many occasions.
You would take the fresh plate and bone it out, then soak in brine. We always brined beef at least 3 weeks, pork 30 days. If I remember correctly we'd pump (inject) the plate beef in the large (brisket) end a bit also as it was so thick. A couple times the plate came out of the brine with non-cure spots in the middle of the meat so pumping was necessary.
Then, hanging on bacon hooks, we'd hang in the afternoon, let dry overnight, then smoke all the next day. We'd smoke them with the regular pork bellies, usually 300lbs. or so total in the smoker (4 rows of bellies 10 in each row, 2 above and 2 below).
Once cooled, we'd slice them into 10 piles, one slice on each pile, shingled on bacon boards (cardboard boards you'd slice the bacon on to then wrap with butcher paper), rotating to each one so there was a variety of slices on each and lay out on a tray in the meat case and it sold for 79¢ lb. Regular pork bacon was 98¢ lb - (60's/70's prices, folks, lol! - little neck clams were 98¢ a dozen too!). It was a once-a-week special for Friday, and if any left, for Saturday, but we usually sold out. Fridays were always special because we got in our beef early that morning and get it broke down and set up the cases by 8am (we'd start at 5). We'd have fresh soup bones and chucks, rounds, briskets, etc., roll the rib and rump roasts, fresh cut loin steaks - it was an exciting day and we'd have at least 2 or 3 meatcutters on the counter waiting on customers too. Mom would come behind the meatcounter and help too, she could crack chine bones and serve up burger, oysters, salads, cut cold meats and bacons, use the hand saw and cleaver; she just did not like the powered meat saw though (watched a former employee cut off three fingers once). Anyways, I digress...
If you can find it, take plate beef, bone it out, pickle it and smoke it. It tends to be tallowy but has good flavor and just another variety that you can do with meats!