Arh, my German was not strong enough to deduce that (and I did not check the English version).
Since all files are included by default, there are not a lot of options to selectively include files. The idea is that most users will want to include everything and then selectively exclude certain files and folders.
It only makes sense to use include rules if you also exclude something, and then the order of expressions then becomes important.
Because of this logic, there is a check for “only include filters”, and if there are only includes, it will default to exclude everything not matched. This is not often used, so the UI does not really help in that case.