Sorry OP I was so mesmerized by the cute mouse interaction in the logo that I didn't yet get around to checking out what this site is about.

Skimming briefly, it looks like a lot of the missing score are some combo of 6-0 and then 0-6. Which makes sense. It's highly unlikely for a set to to be that unbalanced, and then be so unbalanced the other way.

TL;DR

In the Women’s 3-set match, where there are 735 possibilities, these scores have never eventuated:

6-0 0-6 7-5, 6-0 0-6 6-0, 0-6 6-0 7-5

Meanwhile, in the 5-set format of Men’s matches, only 8.5% of the more than 100k result possibilities have occurred.

Then add on a huge UI.