You probably got your answer for this, but for those showing up via Google, here's a few current (as of 2023-04-19) helpful commands that work with Windows 10 (and I assume Windows 11).
As a side note, I never used WinGet to install anything on this PC, so it's nice that WinGet now shows apps that are compatible with WinGet even if they weren't installed with it.
WinGet Version Used: 1.5.441-preview
List Apps with Source = Winget:
winget list --source "winget"
This gives you a filtered list in the terminal that have their source as "Winget". From what I can tell, any app that it can match an ID to in the repository is listed, regardless of how it was originally installed (nice!).
Side tip, you can export this list by piping the output to a file, example:
winget list --source "winget" > "C:\temp\__MyOutput.txt"
Export JSON Manifest of WinGet Programs
winget export -o "C:\temp\__ListApps.txt"
This exports a JSON manifest that can be directly imported using the import command (example below). Change the "C:\temp__ListApps.txt" to whatever you wish. There are a few additional command options you can use: https://learn.microsoft.com/en-us/windows/package-manager/winget/export
Import JSON Manifest of WinGet Programs
winget import -i "C:\temp\__ListApps.txt"
Use this to import that manifest for automated installation. Change the "C:\temp__ListApps.txt" to whatever you wish. Additional info: https://learn.microsoft.com/en-us/windows/package-manager/winget/import
There's also a lot of query functionality so you can filter the lists as you see fit, check the WinGet documentation here: https://learn.microsoft.com/en-us/windows/package-manager/winget/list