https://en.wikipedia.org/wiki/Flatpak

In lay terms, it is a packaging format that allows you to run applications in a sandbox. As a result, your application sits in the same perceived environment regardless on whether it runs on Debian, Fedora, Gentoo, or, with the developed support, on Sailfish. There are limitations that make its use limited, but some we could maybe resolve.

Now, for us, it means ability to run KDE Plasma Mobile apps. In future, with Wayland compositor update, Gdk apps as well. In addition, it also allows to develop using Qt 5.12/5.13 already now.

There is a price to pay. Native look is not available, at least right now. Starting apps takes longer time as container has to be prepared. Keyboard requires special attention and a mod of the app before used. Hopefully, the latter can be resolved and we could use SFOS keyboard.

As a developer, I have distributed Pure Maps and OSM Scout Server via Flatpaks. As a result, I can package it in one place and have it on all desktop distributions. For native look, you have to package separately and write accordingly, as done for SFOS and Ubuntu Touch. For my apps, KDE Kirigami (as in Plasma Mobile) style is used for Flatpaks.