The busybox has a defconfig file. I add/remove items such as
#CONFIG_IP is not set
#CONFIG_IPCALC is not set
But they are not add / remove into installed yocto /bin folder.
type the ip command under busybox $ ip
ip: command not found
I also used
bitbake - c menuconfig busybox
save the changes, and re-bitbake busybox
There is nothing changed in the installed image.