@Ken Maltby: With chrox's fix in, we are, when it's not possible to do otherwise, so, nothing

.
(The sidecar folder is a Kindle idiom, which is why that might sound foreign to you

).
EDIT: In fact, right now, even when we can use a sidecar folder, the settings are stored in both places (the sidecar folder alongside the book, and KOReader's history folder).