I don't really understand what immutable means here. If you install Debian and then never touch anything other than your /home folder (therefore never touching

I don't really understand what immutable means here. If you install Debian and then never touch anything other than your /home folder (therefore never touching the bootloader, any configuration files in /etc, not running apt for any changes/upgrades, leaving the kernel alone, etc.), isn't that "immutable"?