I am a cofounder at Hack Reactor. B2B is our fastest-growing business unit, and this is true for most bootcamps that do B2B. Mostly this is corp training that happens onsite. For example, Company X has 3000 desktop or Java engineers that need to learn JS/web/data science/whatever. GA (and a few others) also has a suite of non-classroom products, which you might see as closer to Lynda or Udacity.