Similar to bug 1224165, but not security related:

The packages listed blow are maintenance updates released into Leap 15.5 that
are missing in Leap 15.6. We should not release openSUSE Leap 15.6 with version
downgrades, and the corresponding functional regressions.

Please pull the content from openSUSE:Backports:SLE-15-SP5:Update into
openSUSE:Backports:SLE-15-SP6, or get a newer package from Tumbleweed. 

asar
awf-gtk2
awf-gtk3
awf-gtk4
civetweb
fwts
glab
htop
keepassxc
lyx
monero
perl-File-Rename
rspamd
seamonkey
stress-ng
xfce4-terminal
xfce4-whiskermenu-plugin