Version 1.20 of @fdroidorg brings some pretty big changes of how repositories are handled:
• official repo is always preferred
• the repo an app comes from is prominently shown
• if an app is available from more than one repo, you can choose where to get it from
• power users can change global repo priorities
When tapping an app, the user sees the app details screen as usual. There, a new box at the top shows the repository the app comes from.
All information on that page including the versions provided for installation are provided by that repo.