Last Updated: 2022-05-26
Unix recommends specific directories for placing certain types of files:
$XDG_CACHE_HOMEfor storing persistent cache files (works with unprivileged processes)
Aside: XDG is "X Desktop Group" - a set of standards. It seems to be used in non-desktop linux installs too.
$XDG_DOWNLOAD_DIRfor storing persistent downloaded files (works with unprivileged processes)
/tmp(etc.) since this gives more flexibility to systems that choose to modify where TMP is.