More specifically, how much wall-clock time did it take, and what was the cost in dollars of the computing power involved?
From shattered.io I see that it took 6500 CPU-years + 110 GPU-years, which tells me roughly how much computing power but nothing about wall-clock time.
This page contains almost what I'm looking for, and it's even from the researchers involved in SHAttered, but it's an estimate dated from late 2015 based on their research up to that point:
Concretely, we estimate the SHA-1 collision cost today (i.e., Fall 2015) between 75K$ and 120K$ renting Amazon EC2 cloud computing over a few months.
Are there up-to-date numbers on what the cost of the actual attack was?