f3read - meaning of the numbers

Thanks for this great helper tool.

But what's the actual meaning of the numbers that f3read tells me?

I'm still on F3 Read 7.2. This version told me

SECTORS ok/corrupted/changed/overwritten
Validating file 1.h2w ... 2097152/ 0/ 0/ 0

I think I read about 2 GB files that were written to the drive as default. But the actual files are all 1 073 741 824 bytes (1.07 GB on disk). So it is the number of 512 kB blocks? Maybe this should be mentioned somewhere - or there would be an output option in other formats.