How are setup modules identified?

[tve]

I read https://github.com/Moddable-OpenSource/moddable/blob/public/documentation/base/setup.md but I can't see anything telling me how I identify a new setup module to the build system. Please point me to the docs for that or add it to the doc:-), thanks!

[phoddie]

Set-up modules are those modules with a module secifier that begins with setup/.