They can have "sub-interfaces" like <top-ns>.<component>.interface.<sub-name>

We use that for protocols and specs at work, e.g., ws.billing-data.interface.specs

I think this also confirms it:

ah perfect, I was just wonder about this

I didn't hear anything. FYI, I subsequently stopped using polyith itself, but replicated its monorepo directory structure while switching to https://bazel.build

And you’re still using Duct?