I think you might be misunderstanding what this does.

You did a search for symbol references that contain "User" ignoring cases.

When you do a search for symbol references this way, Xcode will return two things:

1. A declaration of all the symbols containing "User" and/or some context surrounding the symbol (ignoring Case)
2. Show any places where your code references the symbol

And it did just that.

The first three .swift files show references to symbols that contain "User".
The forth one, User.swift, is in and of itself a symbol that matches the query and has symbols inside itself.
The last one UserViewModel.swift is in itself a symbol as well and all the parts that are nested within that you've annotated with underscores and question marks, serve to give you context about the symbol "UserViewModel", hence the ellipses.

It's essentially telling you "Hey I've found this symbol UserViewModel, it starts with a var named username, has a bunch of stuff following that (i.e. …) then has an extension, then some more stuff (i.e. …) and then ends".

Without knowing what's inside UserViewModel.swift I can't tell if it goofed with giving you a typical declaration, but that doesn't change the fact that its trying to give you context about a valid search result, the symbol UserViewModel, so that you can figure out if that's the one you're looking for.

Keep in mind that variables are considered symbols as well, but in this instance I don't think that's what happened here, otherwise it would've been marked with a P instead of a C.

If this is not desired behavior then I suggest you switch from "Containing" to "Matching Word" or instead consider using the search bar at the bottom of the Symbol Navigator. Another option, if you're searching while going through code, is to right click on the symbol in your code and click Find > Find Selected Symbol in Workspace.

Lastly it might be an idea to go over the Xcode documentation as a refresher. This would be a good starting point.

That said, Apple clearly feels that things can be improved by clarifying, because in the current Xcode beta they've changed the option label from References to Symbols (and added a few more options).