Openwrt dependancies and DEFAULT symbol

Dear all,
There is a behavior i don't understand in the openwrt buildsystem.

I defined a new target:

define Device/kkm_kg01
IMAGE_SIZE := 15744k
DEVICE_PACKAGES := kmod-usb2 kmod-usb-ohci kmod-usb-ledtrig-usbport kmod-usb-serial-cp210x kg01_conf_files
TARGET_DEVICES += kkm_kg01

I want to add a package (kg01_conf_files) if this target is selected so i added my package in the list beginning with the "DEVICE_PACKAGES"

I noticed that my package is NOT selected, however, it creates the following symbol:

Symbol: DEFAULT_kg01_conf_files [=y]

So it seems to do something, but the fact that this symbol is set to yes does not imply any dependency with my real package:

Symbol: PACKAGE_kg01_conf_files [=n] │
│ Type : tristate │
│ Defined at tmp/ │
│ Prompt: kg01_conf_files.......................................... kg01_conf_files │
│ Location: │
│ (1) -> xxxxxx │
│ Selects: PACKAGE_librt [=y] && PACKAGE_libpthread [=y] && PACKAGE_libc [=y] │
│ Selected by [n]: │
│ - MODULE_DEFAULT_kg01_conf_files [=n] && TARGET_PER_DEVICE_ROOTFS [=n] && m && MODULES [=y]

i noticed that it is exactly the same thing with others packages in the list ...
packages are not automatically selected ...

I 'm wondering what i'm missing ?

Can anybody help me ?

best regards