I was working on a Debian machine some days ago.
There I had to use grub2-mkconfig to let Grub scan for OSs installed and create a config file.
It seems like this is normal Grub behaviour and not an addon from the Debian guys.
Back on funtoo I was checking out "grub-mkconfig". However it just created a comment, and not a working grub conf.
I know in funtoo we use boot-update. But I wondered why the "normal grub" behaviour does not work, even seems to be disabled.