First launched in 2018, the open-source SerenityOS offers its users a stripped-back GUI-based operating system that melds a 1990s desktop aesthetic with a focus on productivity for power users. It isn’t Linux, but SerenityOS is a UNIX-like OS, built on a custom core and uses no licensed components. So, while it can run MP3s, other media and related codecs currently covered by licenses are not supported.