может кому ещё интересно будет https://flatpak.org/faq/

Is Flatpak a container technology?

It can be, but it doesn’t have to be. Since a desktop application would require quite extensive changes in order to be usable when run inside a container you will likely see Flatpak mostly deployed as a convenient library bundling technology early on, with the sandboxing or containerization being phased in over time for most applications. In general though we try to avoid using the term container when speaking about Flatpak as it tends to cause comparisons with Docker and rkt, comparisons which quickly stop making technical sense due to the very different problem spaces these technologies try to address. And thus we prefer using the term sandboxing.

Can Flatpak be used on servers too?

Flatpak is designed to run inside a desktop session and relies on certain session services, such as a D-Bus session bus and, optionally, a systemd --user instance. This makes Flatpak not a good match for a server.

However, the build features of Flatpak run fine outside a session, so you can build things on a server.