GIMP Picks Up Support For The New Flatpak/FreeDesktop.org Screenshot API
The org.freedesktop.portal.Screenshot specification aims to be a screenshot API that will work not only cross-desktop (e.g. KDE, GNOME, etc) but also work for sandboxed applications (i.e. Flatpak) and also work regardless of whether you are using Wayland or X11.
This screenshot API is great in theory for finally having a standardized means of capturing a screenshot on the Linux desktop and doing so regardless of desktop, display server/protocol, and supporting sandboxed applications. But in reality this API still to be further improved and also adopted more widely. Currently this screenshot API will take a screenshot of the entire desktop and return it to the requested application. At this point there aren't any more advanced features for being able to do a time-delayed screenshot, only selecting a particular window/region, or anything else found by most other Linux desktop screenshot utilities at this point.
Beyond lacking some common screenshot features, stock GNOME isn't even working with this org.freedesktop.portal.Screenshot specification yet unless installing xdg-desktop-portal-gtk or likewise xdg-desktop-portal-kde for the KDE desktop.
Given these shortcomings, GIMP is relying upon this new FreeDesktop Screenshot API last for now in its screenshot handling process. First preferring the other desktop-specific interfaces and only using this new plug-in if nothing else is available. The details can be found via this commit. Supporting this new screenshot API is just over 200 lines of code for GIMP.