Please ask the authors of the respective application for an officially-supported, upstream-provided AppImage.
Firefox Developer Edition brings your core dev tools together with some powerful new ones that will extend your ability to work across multiple platforms from one place. It’s everything you’re used to, only better. And only from Firefox.
Fotoxx is a free open source Linux program for image editing and collection management. The goal is to meet the needs of serious photographers while remaining fast and easy to use.
FreeOrion is a free, open source, turn-based space empire and galactic conquest (4X) computer game being designed and built by the FreeOrion project. FreeOrion is inspired by the tradition of the Master of Orion games, but is not a clone or remake of that series or any other game.
Fritzing is an open-source hardware initiative that makes electronics accessible as a creative material for anyone.