First congratulations on this project, I am looking forward for development of it. It solves one of biggest issues now with Microsoft Package Management.
I noticed when joining systems to the WinGetty repo and listing for Softwares already installed they appear as SearchId {ProductCode} and not as Wingetty Identifier Publisher.Name, so I cant handle them on winget until I manually uninstall them from system, then install using the Winget install command.
I see on the Official Microsoft winget Manifest repository, most of the packages, each version, it contains ProductCode identifier explicitly stated there. So somehow when winget list is used, it will recognize if the Packages are in the repo.
Solution for this could be to have an extra field whenever new version of package is uploaded to wingetty, so optionally we could state the right ProductCode, like for instance ProductCode: '{7d607fb4-7e28-4c7a-a92f-3fcdaf555faf}' for Microsoft.VCRedist2015
Thanks,