The concept is simple, no doubt. The implementation (IE what the heck
the applicable law actually is in a given jurisdiction) is not. There
are general federal laws that give you a base, but it really does vary
state to state as to what you can get away with in terms of giving no
warranty.
well of course ... that's the whole point of the phrase, it has to be
judged according to the relevant jurisdiction. That's why it is phrased
this way. It's an absolutely standard provision, and there is well
established case law to deal with it.
If German law says you have to provide at least *bla* warranty, then
that's the way things are, and those distributing things under the
GPL must be prepared to provide this *bla* warranty. If they are not
willing to do so, they should be careful about distributing stuff!