Joe Alwyn was the credited co-producer of Taylor Swift’s “august” later publicly identified as William Bowery.
The song’s primary writing and production credits belong to Swift and Jack Antonoff, while Alwyn was recognized as a co-producer after Folklore won Album of the Year at the 63rd Annual Grammy Awards. Alwyn’s production credit is therefore a detail that can be missed when looking only at the album’s original liner-note presentation.
William Bowery was a pseudonym used on Folklore and Evermore credits. Swift later revealed that Bowery was Alwyn, who contributed to several songs connected with those albums. The pseudonym initially prompted widespread speculation because Bowery had no public online identity.
Alwyn is also associated with “betty” and “exile” through songwriting or musical contributions. However, the answer for “august” specifically is Joe Alwyn, not Aaron Dessner, who was another prominent Folklore collaborator.