sh-fotografie wrote:I just can't find it in the folder structure on my server.
Sorry, but it doesn't work like that. Like most other dynamic website applications, X3 forwards all url requests to the PHP script, which then outputs the response. In your case, the feed response is here:
https://www.sh-fotografie.ch/feed/
However, you won't find any actual files in that location on disk, because the request is dynamic and gets cached. I can't really recommend that you try to edit this, as it's based on twig templates, which need to get re-published, and that's why I didn't mention anything previously.
At this point, I am not entirely sure what you want to achieve. There are no built-in methods in X3 for page-specific RSS feeds. I would first see if there was any external service that do what you require. If you can't find anything suitable, and the task is not too complicated, you can always create some custom feed in PHP (although it would definitely be a job).