But then where do files like $this->bbcode_second_pass_code('', '/etc/modules-load.d/raspberrypi.conf') come from in $this->bbcode_second_pass_code('', 'ArchLinuxARM-rpi-2-latest.tar.gz')?
I am pretty sure that when Modaphukka wrote "ISO" he means rootfs tarbal like "ArchLinuxARM-rpi-2-latest.tar.gz".
For sure that pacstrap is used, archiso also uses pacstrap but some tweaks for specific platforms and even initial config files must be create and then package in this roods tarbal.
So, the question is: Where I can found source code scripts used to generated rootfs tarbals?