I checked in the database, and indeed, you gave me the solution.
The table “ttrss-feeds” has the fields “auth-login” and “auth-pass”. I didn’t use them by knowledge, but somehow autocomplete had filled “auth-pass” fields with numbers.
As someone would expect, feeds with passwords shouldn’t be made public, so exactly this feeds were missing from my public OPML file. As soon as I removed the numbers from the table, they where part of my public feed.
This is great, because now I don’t need to export it manually anymore to fill this list of blogs from my hometown “Bonn”: https://bonnerblogs.de/bonner-blogs
I used an manually exported OPML-file on the server and a plugin transforms it to this list.
Is there a way (for you or for me) to prevent this fields to be autofilled (or is there a good reason for this?)