https://wccftech.com/applecare-for-ipad-pro-also-extends-to-the-apple-magic-keyboard/

If you bought the new 2020 iPad Pro along with AppleCare+ for protection, then there is good news for you. Since Apple recently launched its Magic Keyboard, you might want to add protection to it too since it's not cheap and costs a whopping $299 for the 11-inch iPad Pro and $349 for the 12.9-inch iPad Pro. The good news is that the iPad Pro's Apple Care+ now also covers the new Magic Keyboard.

As mentioned earlier, if you have purchased AppleCare+ for your iPad Pro which costs $129 or $5.99 per month, the warranty is extended to the Magic Keyboard. This is the same way AppleCare+ covers the Apple Pencil. However, you will have to pay a service fee of $29 for repairs pertaining to the Magic Keyboard.