This Q was helpful for me so just adding this info for completeness.
The user://
prefix is a Godot-specific thing and wouldn't be recognised in a filesystem search.
According to the File paths in Godot projects page in the official docs, the defaults for what user://
means for each platform are:
- Windows:
%APPDATA%\Godot\app_userdata\[project_name]
- macOS:
~/Library/Application Support/Godot/app_userdata/[project_name]
- Linux:
~/.local/share/godot/app_userdata/[project_name]
Side note: You can also use Project > Open User Data Folder to find the location of the user data folder for your own platform.