It is clear that the results of past runs of a query are stored on Quarry's servers; I was able to find those for my label statistics run on the 25th (compare those from the 26th) after some crawling based on a suspected range of run IDs within which the 25th's results would have fallen.
Is there a way to obtain a list of the results of past runs of a query so that such crawling won't be necessary?