It is actually mentioned on the Wikipedia page [1] - and of course, you could add it yourself if that's not enough.
https://en.wikipedia.org/wiki/WinDirStat#Version_history[10]
Everything I ever added to Wikipedia was removed, within the day, by a very diligent and hard-working Wikipedia person.
Okay, I stand corrected, but I also stand by that it is interesting that it is pointed out that "The project was inspired by SequoiaView" in the lead section, but not that it was a direct port of KDirStat. It feels odd but also intentional, so I never bothered to change it. I'll leave it up to if anyone else feels similarly enough to do so, because then at least that means there are two of us.