CastiaInvTools-forge-1.16.x-2.3.6.jar is a release file of the Minecraft mod Castia Inventory Tools for Forge, made for Minecraft 1.16.3, 1.16.5, 1.16.4, 1.16.2. It was published on August 6, 2021 and is 0.3 MB in size. For the full description, screenshots and every other version, visit the Castia Inventory Tools mod page.
How to install: Put the .jar into the mods folder (.minecraft/mods) and start Minecraft with the matching mod loader profile.