allitems_26.3.zip is a release file of the Minecraft data pack The Ultimate Item Toolkit [1.13-26.3], made for Minecraft 26.3. It was published on September 20, 2026 and is 0 MB in size. For the full description, screenshots and every other version, visit the The Ultimate Item Toolkit [1.13-26.3] data pack page.
How to install: Put the .zip into the datapacks folder of your world (.minecraft/saves/<world>/datapacks) and run /reload. No mods needed.