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It currently displays the username (the users.uname database column) twice, which I agree is probably a mistake.
There are three names: login name, username, and real name. I'm not sure which of the two it's supposed to display, and in which columns on that page.
The code that handles that is in modules/system/admin/findusers/main.php, starting at line 252. The code is a bit hard to read.
getVar("uname") gets the username. getVar("name") would get the real name, and getVar("loginname") would get the login name.
I suspect this code is left over from the split-off of the profiles module in 2.2.x, and was never updated.