a variety of security policies, including mandatory access controls, which Fedora adopted early on. Fedora provides a hardening wrapper, and does hardening for all of its packages by using compiler features such as position-independent executable (PIE). Software Fedora Linux comes preinstalled with a wide range of software such as LibreOffice and Firefox. Additional software is available from the software repositories and can be installed using the DNF package manager or GNOME Software. Additionally, extra repositories can be added to the system, so that software not available in Fedora Linux can be installed easily. Software that is not available via official Fedora repositories, either because it does not meet Fedora's definition of free software or because its distribution may violate US law, can be installed using third-party repositories. Popular third-party repositories include RPM Fusion free and non-free repositories. Fedora also provides users with an easy-to-use build system for creating their own repositories called Copr. Since the release of Fedora 25, the operating system defaults to the Wayland display server protocol, which replaced the X Window System. System installer Fedora Linux uses Anaconda as the system installer. Editions Beginning with Fedora 21, it is available in three editions, expanded to five editions as of version 37. Workstation It targets users who want a reliable, user-friendly, and powerful operating system for their laptop or desktop computer. It comes with GNOME by default but other desktops can be installed or can be directly installed as Spins. Silverblue Silverblue is a variant of Fedora Workstation. It is an immutable desktop operating system. Every Silverblue installation is identical to every other installation of the same version, and it never changes as it is used. The immutable design is intended to make the operating system more stable, less prone to bugs, easier to test and develop, and create a platform for containerized applications as well as container-based software development. Applications and containers are kept separate from the host system. OS updates are fast and there is no installation stage. With Silverblue, it is also possible to roll back to the previous version of the operating system, if something goes wrong. Fedora Silverblue was previously known as Fedora Atomic Workstation. The descriptive name for this product is ​image-mode container-based Fedora Workstation based on rpm-ostree, which is clear but unsuitable for branding. The team preferred the project name Silverleaf, but could not secure that name for various reasons. Therefore,