Hi Ryan, the work is tracked at this milestone - Verification release Milestone · GitHub - which is the list of pre-requisites for the beta release of the website going live with the verification and subset functionality.
Fundamentally it’s not too complicated, Flatpak has support to generate additional summary files for a subset of the repo (see flatpak-build-export manpage) which, if you configure when you add the repo, you only see those apps and runtimes.
The web app looks up whether the app is verified, floss or both, and flat-manager has some flathub-specific hooks which fetch that info at publish time and include it in the commit. They also include it in the appstream metadata, so that the website and any app centre UIs also can display the information consistently. The subsets we’re planning are floss, verified and verified_floss.
Hope that helps!