No, I mean a custom flavor - like how there is standard Raspbian, and also Rasobian boot to Scratch, but there is only one operation system in the os folder. I take it to mean that there must be a way of customising the raspbian os after it has been installed, but am unsure on how to do this for myself.
Really the only mention of flavours in the docs is how to automatically install:
If the OS you want to automatically install has multiple flavours available, edit the flavours.json file so that it only contains the flavour entry that you want to install.
How do I create my own flavour that runs a scrips (say setup.sh) when the install has completed?
Thanks, and sorry for the confusion.