“Brown bottle” Buckfast variant, typically from the Republic of Ireland
This variant is produced by Grant’s distillers in Clonmel, presumably from concentrate. The taste is similar to, but not the same as, “green bottle” tonic wine.
All sorts of bores go on about Wikipedia and how unreliable it is, but any tool that demands a citation for the claim that brown bottle Buckfast tastes different from green bottle Buckfast gets the thumbs up from me. For what it’s worth, I happen to believe that the claim is true, and that green bottle Buckfast tastes superior.