According to the wiki:
Bundles makes sense after solving the movie clip, and it works in the following way: the solved position of each track gets projected back to the movie clip and displayed as a small point. The color of the point depends on the distance between the projected coordinate and the original coordinate: if they are close enough, the point is green, otherwise it'll be red. This helps to find tracks which weren't solved nicely and need to be tweaked.
I am solving the scene and see nothing similar to what's described:
Points are displayed not as points, but as squares, blue means before in time, red means after in time. Yellow or white means selected point.
Where is something green?