[moreresearchplz]

Why should a developer of a free and open-source application, provided free of charge and without any guarantees, have any obligations to package and even test their software on random, thirdparty distributions?

If a distro wants to include their application they have every right in the world to do so. So its up to them to do what ever is necessary to enhance their product with the freely available product of the unpaid developer who created it.

[esarbe]

That's the point of flatpaks - you don't.

You build one flatpak and it will work for all distributions.