vepor

It uses https://www.gatsbyjs.com/ that does all the necessary magic.

It's a design system. You can read about it more here: https://uxdesign.cc/everything-you-need-to-know-about-design...

But basically it's a system how to design and develop applications (mostly mobile or frontend). It contains most of the time some visual foundation, standardized components, guidelines etc.

Yep, sorry, it's probably a bit confusing. The whole design system is open-source, from its components to also the documentation. You can find it on the GitHub repository: https://github.com/kiwicom/orbit/tree/master/docs