This shows the single workers and their jobs. The progress shown (and color) is not for the time it will take (we don't know that before), but just relative against each other. The exact percentage shown has no real meaning, just one thing is certain: the bar reaches its maximum at 4h.
The monitor is meant to entertain and not to be exact, if you need to know more details, check the detailed page.
Repositories to recalculate
Packages scheduled for building