It is not, actually. It's a DMsGuild release by a writer who happens to be a WotC employee (not in D&D). Because he wrote the OG BG games, his stuff has prestige...but they are nit official.
That's fine, those can be perfectly fun. But much like driving a Ferrari 10 miles under the speed limit only to the grocery store on Sundays, it's not quite the design intention.