Tvix is a new implementation of Nix, a purely-functional package manager. It aims to have a modular implementation, in which different components can be reused or replaced based on the use-case.
Warehouse Alternatives
Warehouse is described as 'Versatile toolbox for managing flatpak user data, viewing flatpak app info, and batch managing installed flatpaks' and is a Package Manager in the os & utilities category. There are more than 50 alternatives to Warehouse for a variety of platforms, including Linux, Mac, Windows, Flatpak and Flathub apps. The best Warehouse alternative is UniGetUI, which is both free and Open Source. Other great apps like Warehouse are Ninite, Chocolatey, MacUpdater and Homebrew.