XDG_DATA_HOME seems strange for MacOS

[martin-braun]

You set it to ~/Library/Application Support on MacOS. From my own experience, all MacOS Applications, such as Cocoa apps, use this directory, but most of the CLI tools use ~/.local/share by default. This is what I observed using Unix-tools without XDG variables set over the years, so I think it should remain ~/.local/share, because anything that want's to read XDG variables, is asking for some universal Unix path.

To me it makes sense to keep those things separated.

I agree though, I'm looking through this through the environment CLI lens, this is a Go package. If Go is used to package a traditional MacOS application, it makes sense.

The same applies for CONFIG. For XDG_CACHE_DIR though, I kinda agree it's better to set it to $HOME/Library so unimportant files can reside in a single location, with the assumption that tools will follow the XDG specification.