SUMMARY Flatpak uses deltas for updates, and the amount downloaded is always less than the full installation size. For example, running 'flatpak upgrade' from a terminal, Flatpak shows that less than the full size will be downloaded: ID Branch Op Remote Download 1. org.freedesktop.Platform.openh264 2.5.1 i flathub < 971.4 kB Discover shows the full amount, indicating to the user that they may need to download 971.4 kB (Discover shows in KiB/MiB, so the amount is different anyway). If this shows a large number, for example when a runtime is updated, it will likely show hundreds of MB or even several GB, then the user might put off that update thinking it might use too much of their data cap or take too long. The reality is, it will only download a portion of that. This could be bad if the particular update is because of a security risk. We don't want users putting off updates due to time or size issues.
A possibly relevant merge request was started @ https://invent.kde.org/plasma/discover/-/merge_requests/1226