When selecting display resolution, 32:9 resolutions are not marked as such
In GNOME Settings, on the page Displays, while the display resolution dropdown correctly adds an aspect ratio hint in parentheses for resolutions with aspect ratios 21:9, 16:9, 16:10 and 4:3, it fails to mark 32:9 (resolutions 5120x1440 and 3840x1080), see here:
This was reproduced on Pop!_OS and Fedora, so most likely a GNOME issue.
To reproduce, if you don't have a 32:9 screen (I do recommend), it should probably be enough to temporarily add the resolution using xrandr.