Used only when `HF_HOME` is not set!  
This is the default way to configure where [user-specific non-essential (cached) data should be written](https://wiki.archlinux.org/title/XDG_Base_Directory)
on linux machines.  
If `HF_HOME` is not set, the default home will be `"$XDG_CACHE_HOME/huggingface"` instead
of `"~/.cache/huggingface"`.