At first it looks like iCloud Drive preserves all xattrs, but actually it cheats and show those stored locally. It’s different when you access the same files from another Mac.
metadata
Two metadata editors, and an app to improve your privacy by cleaning metadata and more. Updated for High Sierra and later.
Where to look for file metadata in the Finder, and how you can customise it, in spite of its apparent confusion. And how APFS takes care of extended attributes for you.
Finder Comments are accessible, easy to use, and unreliable because they rely primarily on data stored in a hidden file. Regular Comment extended attributes are more reliable.
Turning the data blocks into files and directories, these have common functions and additional features which can give rise to tricky problems.
Useful metadata shown in two places, and available as columns in List views. But some things don’t match up, and information changes in front of your eyes.
So convenient to use – edit them in the Comments: section of Finder’s Get Info dialog. But as reliable as loose scraps of paper, and as easily lost.
Unlike file data, metadata has varying persistence. Some is ephemeral, others sticky. macOS has inbuilt mechanisms for managing the persistence of extended attributes.
All about xattrs: their origin, where they’re stored, how they’re named and typed, how to find and work with them, and their common problems.
Tools for editing metadata which is generally well-preserved, including copyright and keywords. Now native on all Macs.
The Eclectic Light Company 