The Minecraft launcher uses Chrome to display its interface, and Chrome creates a directory called GPUCache. Minecraft current stores it in the user's home directory. All other programs that use Chrome are kind enough to tuck it away somewhere.

I propose that the Minecraft launcher should do the same and place it in $XDG_CACHE_HOME/minecraft/GPUCache, so as to not clutter up user's home directories and to follow the XDG spec.