I'm not sure this is the right place to post bugs.
Anyway, here it goes:
Mixed Content: The page at 'https://developer.cisco.com/site/neXt/learn/' was loaded over HTTPS, but requested an insecure script 'http://d3js.org/d3.v3.min.js'. This request has been blocked; the content must be served over HTTPS. loadScript @ next.js:95
It happens when trying to use the "US Map" demo.
It can be easily fixed: just use the "//" schema instead of specifying "http://" schema explicitly.