Flatpack offers hints. FAQ includes :
Is Flatpak a container technology?
It may be, but it is not necessary. Since the desktop application will require quite extensive changes so that they can be used when running inside the container, you will most likely see that Flatpak is mainly deployed as a convenient technology for linking libraries at an early stage, while for most applications, phased sandboxing or containerization with time.
In general, although we try to avoid using the term container, talking about Flatpak, since it tends to cause comparisons with Docker and Rocket, comparisons that quickly stop making technical sense due to very different problem spaces, these technologies try to address . And so we prefer to use the term sandbox.
Is Flatpak related to Linux?
Yes. We explicitly use many of the linux kernel features (bind mounts, namespaces, seccomp, etc.) to create a sandbox in which Flatpak applications run. It may be possible to use equivalent technologies for other cores, but this will be a non-trivial amount of work, and we will not consider this one of our priorities.
The container is designed to provide isolation on any system that implements its runc / containerd protocol, and will soon work on both Windows and Linux.
This is different from a software packaging format that is fully OS-specific.
See " Flatpak, Appimage And Snap - How Do They Drain? "