It seems like only the larger companies working on development and design frameworks are producing interactive documents that provide information about the visual and interactive design components/elements. I am making this assumption because in projects where I have advocated for the creation of such assets, it is usually met with much resistance due to the perceived effort required to create them, and the perceived value of such assets in guiding the design and development effort. That's not to say other companies don't create them and maintain them internally, but certainly they are not see out in the wild.
With the relaunch of Google Design (including Material Design guidelines), changes to the Atlassian Development Guide and even Uber's new brand guide, shouldn't we be moving towards a web based and interactive form of documentation because it suits the way that UX design and standards evolve?
Some interesting references that people might like to have a look at as well:
http://patternlab.io/resources.html
UPDATE: Styleguidist and Storybook have definitely popularized the more interactive types of style guide / design systems being published on the web as part of the design and development process