Remove from Device vs Delete this book
 

I have two PW4 Kindles. I've seen both messages at one time or another. Different firmware versions or different actions. Neither one seems to remove the book from the cloud.

Both just delete the book from your device.

The "remove" message is shown for books that are associated with your Amazon account. The "delete" message is supposed to be shown for sideloaded books, but I have occasionally seen it appear for downloaded books. That is probably caused by a bug in Amazon's software.

I have only Kindle books. Thanks.

Which FW? I noticed a change since 5.12.4, still same at 5.12.5. When I return KU books from the device, they get removed from the cloud and no longer marked as KU, but remain on device. It changes from "return to KU" to "delete". Might be related or not to your issue.

I don't have Kindle Unlimited so I don't know. Neither the "remove" or "delete" removed books from the cloud and I've never had a book removed from the cloud that stayed on a device. I might never have tried that.

I am just saying that the behavior is different now. It used to be that if a book is returned to KU, it will be removed next sync or instantly if the return happened on device. Not sure if regular library books are also effected the same way.

I don't believe there was ever a way to delete books from the cloud directly on a Kindle.