IM-BT [1.8.9].zip is a release file of the Minecraft resource pack Bits And Tweaks, made for Minecraft 1.7.6, 1.8.7, 1.7.4, 1.7.7, 1.7.5, 1.6.1, 1.8.4, 1.7.9, 1.8.8, 1.7.3, 1.7.2, 1.8.3 and more. It was published on February 20, 2025 and is 30.9 MB in size. For the full description, screenshots and every other version, visit the Bits And Tweaks resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.