Backrooms Map 1.21.6.zip is a release file of the Minecraft map Backrooms Map 2 (because you can't give the name of something that already exists), made for Minecraft 1.21.6. It was published on July 18, 2025 and is 288.5 MB in size. For the full description, screenshots and every other version, visit the Backrooms Map 2 (because you can't give the name of something that already exists) map page.
How to install: Extract the .zip and move the world folder into .minecraft/saves; the map then appears in your Singleplayer list.