Minecraft_HD_64xRP..zip is a beta file of the Minecraft resource pack Minecraft Default HD 64x, made for Minecraft 1.7.4, 1.6.1, 1.7.2, 1.5.2, 1.5.1, 1.6.4, 1.5.0, 1.6.2. It was published on May 14, 2014 and is 8.1 MB in size. Pre-release builds can contain bugs — back up your world before installing. For the full description, screenshots and every other version, visit the Minecraft Default HD 64x resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.
