The Chef-branded distribution is still built from the same open source repositories that the CINC project is built from; it isn't proprietary. It has an additional EULA that requires people to accept and thus [presumably] pay for.

It's basically the same model as Red Hat. Except Chef never had the market penetration and brand recognition as a trusted source that Red Hat has.

Signed, someone who worked for Chef for almost 13 years.

Huh. Given Ruby/Chef lost, are the Chef maintainers going for a final financial squeeze of whoever is still on the platform?