Calamares is the initiative by members of Kubuntu, Fedora, Manjaro, KaOS, Maui, Netrunner, and others to provide a generic framework for allowing Linux distributions to use these basic building blocks for constructing their installer. Calamares seeks to provide all the critical features needed by the different Linux distributions and their installers.
Calamares 1.0 is a completely modular design with three plug-in interfaces, C++ and Python API support, 25 different modules for extending the base framework, a self-contained branding component, an advanced partitioning tool, and various other features.
Those wishing to learn more about this weekend's Calamares 1.0 release can find the release announcement. Already the Arch-based Manjaro Linux distribution is using the Calamares-based installer going forward.