Amazon says the 2026 Signature Edition cover is more than 70% renewable bio-materials (primarily non-GMO corn, and viscose fibre from Forest Stewardship Council-certified sources) and the remaining content is polyurethane.

Most consumer leather has a pigmented acrylic or polyurethane topcoat and then dyes and fat liquors. Chrome-tanned leather leaves chromium behind when it breaks down, potentially into the toxic hexavalent form. "Biodegradable" has no time limit attached, so it doesn't really say much about the "green-ness" of animal leather. Tanning itself is done to slow down biodegrading.

All of this is orthogonal to the fact that I, personally, as a consumer, do not want to purchase a product made from animals, which is why I'm glad they're not making them out of animals anymore.