Z:gnu-www-ja-gpl-faq--cb747a-The last sentence of the first/en

The last sentence of the first paragraph of section 13 is only meant to reinforce what most people would have naturally assumed: even though combinations with code under GPLv3 are handled through a special exception in section 13, the Corresponding Source should still include the code that is combined with the Program this way. This sentence does not mean that you only have to provide the source that's covered under GPLv3; instead it means that such code is not excluded from the definition of Corresponding Source.