when index.html is not index.html

Hi folks,

This is interesting.

I noticed that a company showed up twice on the same Google search.
Once on page one rank #3 and the second time on page two rank #6. Same
domain name.

The only difference that I can discern is that one is its company url
"www.XYZ.com" (page 2) and the other is "www.XYZ.com/ABC/index.html"
(page 1)

Clearly, the page 1 is not the "index.html" as we know it
conventionally. Is this a loophole that Google has not found yet or is
this a legal maneuver?

Curious,  YFJ