> I would not want a program to have access to all cache data for every program. Then XDG_CACHE_DIR doesn't change anything? The path is going to be $XDG_CACH

> I would not want a program to have access to all cache data for every program. Then XDG_CACHE_DIR doesn't change anything? The path is going to be $XDG_CACHE_DIR/$PROGRAM which is what would get allowed (and neighbour subdirs disallowed); no program would get to see the others' cache. I just checked and I have a ~/.cache/firefox right there. Having it at a single root point means it's trivial to make all cache ephemeral in any way one chooses.