The docs for symbolicating a crash file state:
To symbolicate in Xcode, click the Device Logs button in the Devices and Simulators window, then drag and drop the crash report file into the list of device logs.
However, this button is no longer available on Xcode 15 (now replaced by a "Open Recent Logs" which opens a Finder window). Is it possible for the docs to be updated? What is the solution in Xcode 15?
Unfortunately I've found the same issue.
For now I'd suggest using Xcode 14 to symbolicate crash logs, or via terminal using atos - something similar to this works well (although I used ChatGPT to generate a convenience script for me).
Simplhy use "Open Recent Logs" and select the .crash file (renamed from .txt) you want to symbolicate
This does not actually symbolicate the crash log for me. I filed FB13543963 about this.