openbsd
OpenBSD is a Unix-like operating system in the BSD family. Initially forked from NetBSD in the mid-1990s, it has since become noteworthy for its pioneering work in software security and heavy use of cryptography.
Unusually for an operating system, new releases are usually accompanied by posters and songs. Most of these feature OpenBSD's mascot, Puffy the pufferfish.
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This tag implicates bsd (learn more).