The set looks like it's a grab bag of stuff from the first season. Not a bad collection, on the whole, though there are a couple I would have left out and a couple others I would have included.
I don't know if this is an official WB release or not. I looked on amazon.com, and could not find any Animaniacs DVDs (no surprise there). This set is also stated to be region-free, something I have a really hard time believing that WB would do. OTOH, the seller is in Greece, and it is not outside the realm of possibility that they'd do something like that over there...