If you install it, cached kernels will go to either $HOME/.hashcat/, if that already exists, otherwise to $XDG_CACHE_HOME/hashcat/ or ~/.cache/hashcat/, if that environment variable is not set. Session files, restore- and pot-files etc. will go to either $HOME/.hashcat/, if that already exists, otherwise to $XDG_DATA_HOME/hashcat/ or ~/.local/share/hashcat/, if that environment variable is not set.