After long contemplation and because I lack access to the book and I don't know which I should track down second-hand, I ask the community:
Hengeyokai (WW 03063, published 1998) references on page 174 the following:
Of course, the guidelines for cross-Gift learning given in the Werewolf Players Guide (pg. 189) should be followed fairly closely [...].
In trying to figure out what is meant to be a Kitsune's benefit when learning gifts of other Breeds/Races/Auspieces – which according to the quote is detailed there – it is eluding me which version of the Werewolf players guide is meant: There are two: First and second edition, and sadly they share exactly the same name.
So which one is meant?! The old or the new?