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 & 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.