cinnamon depends on gir1.2-gkbd-3.0 and gkbd-capplet, and uses
libgnomekbd (via libxapp) for keyboard layout handling. libgnomekbd is
dead upstream (#1092927) and its removal from Debian has been proposed
for the forky cycle.

It appears that this dependency will go away when cinnamon is updated to
version 6.6.

    smcv