>>21482198No. Extra dry butter is not a legal term in France, it's meaningless babble. If butter doesn't contain 82% fat it's required to add "light" or "salted" to the label which signals the use of thickeners and preservatives.
For butter there are 3 legal subdivisions: raw milk ("cru"), fine butter ("fin", made with frozen pasteurized milk) and "extra fine" ("extra fin", made with pasteurized fresh milk).
The term "beurre de baratte" doesn't mean anything. It simply means "churned butter", you can't make butter without churning it. 90% of French butters (including this one) is made exactly the same as all butter anywhere, because it's cheaper and can be mass-produced but it lacks a complex flavour profile.
For a good butter to develop, the cream is allowed to mature first, it's then allowed to ferment slightly before it's slowly churned. It's more difficult to accomplish, more time consuming and of course more expensive. Industrial butter doesn't let the cream mature, churns too fast and injects the fermenting lactic acid bacteria at the end of the process. Whether a butter has 82 or 84% fat is of little importance.
There are 5 registered butter regions worth looking out for: Poitou-Charentes (Echirรฉ, Bordier), Les Charentes, Isigny, les Deux-Sรจvres and Bresse. The very best comes from Le Ponclet in Brittany however.