@iaTa:
Try with a fresh download, the package's okay on my end.
Code:
...
Device Kindle Basic 3 (2019)
Device White Kindle Basic 3 (2019)
Critical 0
Padding Byte 0 (0x00)
MD5 Hash 59d0f84f548160635ed3030fc30d3c7e
Metadata 7
Metastring PackageName=KUALBooklet
Metastring PackageVersion=054f614
Metastring PackageAuthor=ixtab, NiLuJe, twobob, stepk, coplate
Metastring PackageMaintainer=coplate, NiLuJe
Metastring PackagedWith=KindleTool v1.6.5.145-g904e090 built by portage@illyria on Gentoo
Metastring PackagedBy=niluje@illyria
Metastring PackagedOn=2019-06-18 @ 01:47:47 UTC
(The same metadata info should be logged by MRPI, that should help you confirm you had an older package

).