Store cache in $XDG_CACHE_HOM or ~/.cache

On linux, /tmp is most of the time an in memory filesystem, wipe out after a reboot.

So for a long term cache, this does not work, unless you can specify a custom location.
I can't find out how to specify a said custom location. Where is the doc? How do you use FileSystem() or LocalFileSystem() (not really user friendly API)

You should be able to choose where the cache is stored, and a default location better be $XDG_CACHE_HOME if set or else $HOME/.cache on linux.

/tmp is for temporary file not cache