conf file - where is it ?

[Catonano]

After quite some time I run Guix again, this time in a Qemu based vm

With the vm provided on the download page

The manual (linked from the download page, it's here
https://guix.gnu.org/manual/en/html_node/Running-Guix-in-a-VM.html ) says
that the configuration file used t produce that image is in the tree

But I can't find it

I'd like to reconfigure my machine but using its own conf file as a
starting point

Thanks