Is there any form of propagation of metadata onto the local filesystem, like tags? For example stored in extended attributes or a separate metadata file?
For the purposes of editing tags in the local filesystem or taking advantage of tags in the local filesystem I’m asking this question.
Not yet, although I recall filling an issue specifically requesting integration between Nextcloud (although it may have still been owncloud then…) tags with the operating system’s native tags. Personally I’m in favor of using both extended metadata attributes and sidecar files, and then propagating between them when one is missing data, as both extended attributes and sidecar files have scenarios where they may fail.
As a private user, you can add some money on specific issues to push them via https://www.bountysource.com/teams/nextcloud
and for larger setups and companies, they can buy official support with Nextcloud. Or you programm it yourself.
I’m not sure how well tagging is implemented on different operating systems, but when it comes to backups, you probably want to restore such information as well. That can be a bit complicated. Therefore, I still use folders.