We have launched a trial of shipping the official Signal releases in our F-Droid-compatible repository. We believe we can reliably ship them, using multiple layers of verification on top of the built-in APK signature Signal Foundation ships. This is the same setup that ships Tor Browser. We welcome feedback.
@knitter The core goal is to push Signal towards free software, and to make Signal available via channels that users already trust. The ideal outcome would be if Signal Foundation maintained Signal on @fdroidorg via reproducible builds.