Update: Here are the direct links for the working KUAL Booklet:
Direct Download:
https://storage.gra.cloud.ovh.net/v1...0250419.tar.xz
Official Source/Thread:
https://www.mobileread.com/forums/sh...d.php?t=225030
The "Update_KUALBooklet_c6ac782_install.bin" file is included in the tar.xz archive. Extract it and place it in the mrpackages folder on your Kindle. This version works on Paperwhite 12 gen.