In short: A new codename, "Kalista," has been spotted in the Chromium code repositories along with a couple lines of code that could point to a new wave of non-standard Chrome OS devices is in the works. The code shows Kalista being added as a new baseboard, implying that the codename doesn't refer to any single or individual device but is a reference design. It is also indicated as having no 'embedded' Chrome OS keyboard, instead utilizing 'legacy keyboards.' That would seem to suggest that a new generation of Chrome OS devices in the Chromebox, Chromebit, or Chromebase categories are on the way.
Background: There really isn't much to go on for the time being since Kalista was only added to the repository over the past week. It does, however, appear to incorporate Intel's Kaby Lake series processors. That encompasses the company's 8th-generation chips, meaning that the devices built on this baseboard could be comparatively powerful for devices running the OS. That's not necessarily surprising, given the decidedly 'premium' shift Chrome OS has taken over the past several months but could also provide another clue as to what form factor the devices will take. Kaby Lake is already in use in Chromebox hardware via the "Fizz" baseboard. Unless some other hardware changes are being made that prevent more direct branching or some other change is rendering Fizz obsolete already, that could mean that Kalista isn't meant for that platform at all.
Meanwhile, the use of a legacy keyboard rather than a Chrome OS-specific keyboard stands out. Unless the code is changed at some point in the future, legacy keyboards are those that don't feature a Chrome OS layout, with the usual system control keys, search button, etc. – more typically associated with a Microsoft or Apple desktop. Taken collectively and setting aside Chromebox hardware, that could mean Kalista is intended to underpin a new range of all-in-one Chromebases or Chromecast-like Chromebit.
Impact: Meanwhile, it can be stated with near certainty that Kalista does not point to a new Chrome OS tablet or Chromebook. In both of those cases, the code is typically included for either an on-screen software keyboard or for keyboards following one of two Chrome OS layouts. Chromebase might be out of the question too since those generally ship with a dedicated keyboard and mouse. With Chrome OS beginning to abandon its entry-level netbook image, Kalista may be the first indication that Google and manufacturers are preparing to take on more traditional computers as well.