It's a newer fake sugar replacement:
Allulose is a sweetener that tastes like sugar but contains minimal calories and carbs. This article examines the safety and health effects of allulose.
www.healthline.com
Available on Amazon:
Amazon.com : Allulose Non-GMO 32 oz 2 LBS Pure Crystalline Powder Sugar-Free Low Calorie Zero Net Carb Keto Diabetic Friendly Natural Sugar Replacement Sweetener No Sugar Alcohol Soy-Free Gluten-Free (1 Pack) : Grocery & Gourmet Food
www.amazon.com
I had a family member staying with me for a few months who was sugar sensitive, so I tried out pretty much everything on the market over ten weeks or so to accomodate them & see what was out there for low-carb options. I don't like Stevia at all, can't stand the aftertaste especially. Not real fond of monk fruit. Sucralose is pretty decent. Allulose is surprisingly good...not quite as sweet as sugar, but very similar, so you have to adjust your recipes as required. I made some mini cheesecakes with it & they were pretty decent!
I'm not real fond of fake sugars in general, especially in diet sodas, but Sprite Zero tastes really close to regular Sprite, and Fresca Original is actually pretty dang good! Polar makes some really good diet sodas...they're not perfect, but you get used to the taste pretty quickly. I compiled a list of pretty good low-carb options here:
It's grown since then, but overall I was pretty impressed with how far things have come. There's a lot of surprisingly good-tasting options on the market for sugars & other sweeteners like water enhancers & sodas, and even stuff like Allulose for baking!