main menu clearly shows which expansion are installed

game/engines/default/engine/Tooltip.lua

game/engines/default/modules/boot/class/Game.lua

...default/modules/boot/data/gfx/dlcs-icons/ashes-banner.png

...ngines/default/modules/boot/data/gfx/dlcs-icons/ashes.png

...default/modules/boot/data/gfx/dlcs-icons/cults-banner.png

...ngines/default/modules/boot/data/gfx/dlcs-icons/cults.png

...efault/modules/boot/data/gfx/dlcs-icons/embers-banner.png

...gines/default/modules/boot/data/gfx/dlcs-icons/embers.png

...nes/default/modules/boot/data/gfx/dlcs-icons/no-ashes.png

...nes/default/modules/boot/data/gfx/dlcs-icons/no-cults.png

...es/default/modules/boot/data/gfx/dlcs-icons/no-embers.png

game/engines/default/modules/boot/dialogs/MainMenu.lua