These keymaps differ from the usual xkb mappings for the us and cz keyboards mainly in that they have more mappings on the third (AltGr) and fourth (Shift-AltGr) level.

On my Arch Linux machine with LXDE, the mappings are located in /usr/share/X11/xkb/symbols/ and the icons are in /usr/share/lxpanel/images/xkb-flags/