> I don't know where to look at the source code
If you are sure, I can send you the patch diff of acqlite core code. To save your time.

>Only thing that I can say is that they connect to 5 UPs per default. Looking forwards for the "fixes"

>When searching, it sends What's New requests to 4 ultrapeers instead of 2,
No, it's not true. acqlite prefers default '2' peer What is new query.

> "uses an
unusual default for the number of connections that leaf nodes maintain to ultrapeers: 5 instead of 3." That's sucks.

It's not sucks.
I know 5 connection is LimeWire's default. I think it's not problem.