UGH, these kinds of bundles annoy me. I don't want the physical or audio book, I just want the e-book and the supplemental materials - I will never want/need th

UGH, these kinds of bundles annoy me. I don't want the physical or audio book, I just want the e-book and the supplemental materials - I will never want/need the audio or physical book, and yet it increases the markup a ton. Actually, I don't even care for the interviews, but I'd like to know what this "supplemental" material is before I'd ever consider that complete package.