Space Bucket.zip is a release file of the Minecraft resource pack SpaceBucket UI, made for Minecraft 1.8.7. It was published on August 10, 2015 and is 2.8 MB in size. For the full description, screenshots and every other version, visit the SpaceBucket UI resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.