This repository hosts unofficial Flatpak manifests for Scribus. A development and a nightly version is available, with the latter being available pre-built. You can find the list of known issues here. Testing and contributions welcome!
You will need Flatpak installed.
You can install the nightly version of Scribus either by clicking on this link, or using the command line:
# Install the nightly version flatpak install http://drjurf.tk/scribus-flatpak/scribus-nightly.flatpakref
(The development version is no longer available pre-built, it was too resource-heavy to maintain both versions, but you can still build it yourself.)
You can find the source code on GitHub.