Where is the right place to ask flatpak developer questions?

I want to create a flatpak and run into serious problems. There is a mailing list but it seems to be dead. Is there any forum that is more active. And i hate mailing lists, they are so 1990s style of communication.

You can ask here, devs are monitoring the forum.

Live-chat might be more responsive though: https://matrix.to/#/#flatpak:matrix.org