You can clone with
HTTPS or Subversion.
I frequently use scraperwiki.com to doodle example data visualisations, and it will only pull in thrid party libraries via https.
Is there any chance of making the sigma.js libraries aviailable, at least for testing purposes, someone obvious here on github, so that they can be accessed from https requiring demo sites such as scraperwiki?
I currently have no idea where to put a stable version of sigma.js on a https-secured domain. Maybe http://cdnjs.com/ could be the solution, I'll try to submit it when the new version is a bit more stable.