History of Brass Gardeners

Brass Gardeners is a lore entry triumph from the Inspiral lore book, added in Lightfall (28 Feb 2023). Its objective counter shows 0/5 progress. The entry text describes "a specter of the Black Garden, rich with the sweetness of flowers and the stink of Radiolaria" and is cryptic, data-like writing.

How to unlock

Destinypedia says Inspiral entries are unlocked by interacting with green bowls in the Root of Nightmares raid, completing some of its encounters, opening secret chests and the red border chest. Which of those gives Brass Gardeners specifically is unconfirmed in the sources I opened, and what the five progress steps are is also unconfirmed.