GitHub bi-colour timeline graphs are back.

... 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.