[manwe150]

Not to be too annoying, but that file is how it supports the feature on non-posix-compliant file systems (usually FAT). On filesystems that support file-streams (or the original HFS), that metadata is stored on the file itself

[p_ing]

You're thinking of resource forks. .DS_Store is stored as ".DS_Store" even on APFS.

[alt227]

Considering how pushy Apple normally are when it comes to forcing their customers to use new things so they can obselete old ones, I am very surprised where Apple have drawn the line in supporting older systems.