Only vacation. I think 20 is the legal minimum on full work day vacations that the company must give if you work 5 days a week. On top of that there are 14 national holidays. Normally companies in Germany give their employees 28 to 30 days, so 25 isn't that great.
Sick leave does not count towards any of those, if you're sick then you don't go to work and you still get paid - as simple as that. If you get sick while on vacation those days then count as sick leave and not vacation.
Probably it's just vacation, holidays are separate and sick time is its own whole thing. I work for Google in Munich and the vacation time is 30 days as they say, and then a bunch of holidays (actually about the same as Google in the US due to weekend handling) and of course sick time is available.
