Right now you can configure most of the build options like custom packages and repos through ./configure options, but there's no way to store that data somewhere for reuse.

Another related issues are that many things that should be data are now code (e.g. default mirror URLs), and other options such as kernel version are again getting scattered across multiple files. Other things such as kernel flavor are hardcoded in scripts/live-build-config which also hurts build flexibility and users' ability to make custom builds.

It's probably a good idea to move all such defaults to one file, and add a ./configure option for using a file other than the default.

I suggest a JSON file at data/defaults.json and an envionment variable VYOS_BUILD_FLAVOR so that people can do:

VYOS_BUILD_FLAVOR=/home/jrandomhacker/cool-vyos-flavor.json ./configure
sudo make iso