Looks like it uses a "Yocto" script - https://github.com/elk-audio/elkpi-sdk - https://www.yoctoproject.org/

I thought of Ubuntu Studio as well, but it looks like Elk is intended to be more lower-level / for appliances. I'm not totally sure though, but I'm guessing it doesn't come with the full suite of Ardour etc.

I do wish there was something like Ubuntu Studio, except focused on audio-only (and more polished / supported). Mostly just because JACK + low-latency kernels are an ordeal to set-up and maintain on a normal desktop, so it's much easier to just install a pre-configured distro on a studio computer and be ready to jam whenever inspiration strikes. Unfortunately KXStudio as a separate distro isn't around any more. I still use a KXStudio 14.04 install on an old (airgapped) DAW computer.