I am using WinHTTrack Website Copier 3.23 (+swf).

Within the title bar of the HTTrack window, a progress 
description appears of the form:

Site mirroring in progress [7886/8218 (+1), 610259796 bytes]

What is the meaning of the (+1)?  Yes, I know the second 
number grows, but what is occurring dynamically?  Why are 
new links being uncovered so late in the process?