These fonts are buggy (e.g. bug 152358) and they are orphaned with no upstream. The last versions of these fonts were prepared by me, over a decade ago, when I was still believing these are FOSS fonts, but I’m no longer sure about their legal status. They disappeared entirely from KACST website where they were once hosted, and attempts to get in contact with anyone who knows anything about them failed. They appear to be clones of other non-free fonts, so the whole thing is shady.
Khaled Hosny committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/6d6a2343b1d45695f3ea02818d317a022a7b259f tdf#152376: Remove Kacst Book and Kacst Office fonts It will be available in 7.5.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Thanks, Khaled
Verified that KacstBook and KacstOffice are gone in: Version: 7.5.0.0.alpha1+ (X86_64) / LibreOffice Community Build ID: ad085990b8073a122ac5222e5220f8f1d6826dcf CPU threads: 8; OS: Linux 5.15; UI render: default; VCL: gtk3 Locale: en-AU (en_AU.UTF-8); UI: en-US Calc: threaded