=AVERAGE(LARGE(A1:A60,ROW(INDIRECT("1:10"))))

This array formula averages the 10th largest values in the Range A1:A60,
I understand it:

so its taking the average value of

LARGE(A1:A60,1), LARGE(A1:A60,2), LARGE(A1:A60,3)..........

But how does ROW(INDIRECT("1:10") return the array 1,2,3,....


Thanks