Original ask: Because we are not running astropy in someone's home directory, I want to be able to set the download/cache directory to someplace different than ~/.astropy/downloads. How do I do that? Setting environment variables (e.g., $HOME or $XDG_CONFIG_HOME) is not an option because that may affect other apps in unintended ways.

Might be related:

• Why doesn't astropy use ~/.config/astropy by default (on Unix-like systems)? #6803
• Cache for test files #8748
• Persist astropy cache #9557
• Use user-specified custom cache directory #10244
• Config woes meta-ticket - add ASTROPY_CONFIG_DIR and ASTROPY_CACHE_DIR #10738

cc @ejeschke