GitHub bi-colour timeline graphs are back. (github.com)

... But appears not to have rolled out for most people (presumably the old setup stuck until the render cache clears).

By way of explanation:

  <canvas data-color-all="#e0e0e0" data-color-owner="#4183C4"
  data-source="/ab9/simple_authentication_starter/graphs/owner_participation">
  </canvas>

Each timeline is drawn in a <canvas> element. Each element uses the data-src to grab a JSON blob with "all" and "owner" keys, and uses the color-owner and color-all attributes to figure out which colours to use when drawing them. Kinda neat.

Not a peep from GitHub about this officially, unfortunately, regarding both it going away or coming back.