- IPv6 - It's 2023 and it's still not deployed correctly and universally. Github, Github Copilot, Chromium-based browsers, and Amazon Alexa give up in the presence of IPv6.
- DNSSEC+DANE - It's half-assed deployed but there's a lack of end-user UX
- wais - search before gopher
- afs - distributed fs
- discard protocol - basically, a network-based /dev/null
- humans.txt - Not around as much as it was
- makeheaders - Auto-generated C/C++ headers
- man page generators - ronn and help2man
- checkinstall - The automatic software package creator
- bashdb and zshdb
- crystal - Compiled Ruby-ish
- forth - Powered the FreeBSD bootloader menu for many years and word processors (typewriter-like almost computers)
- ocaml - The best ML, used by Jane Street and Xen
- pony - A language built around an arguably better GC than Azul's C4 with arguably stronger sharing semantics than Rust
- prolog - Erlang's grandpa
- rpython - PyPy's recompiler-compiler
- pax - POSIX archives
- shar - shell archives - Self-extracting archives that look like scripts at the beginning
- surfraw - Shell Users' Revolutionary Front Rage Against the Web - founded by Julian Assange
- step-ca - A Go-based PKI server
- dmraid - Because it works
- X10 - Before WiFi and IoT, there was the Firecracker: a parasitic power serial port RF outlet controller
- FreeBSD - It's not unknown or obscure per se, but it powers many important things in the civilized world without getting much credit
- :CueCat - A dotcom era barcode reader that was given away
- Xen - If you need to run a VPS but can't ju$tify u$ing VMware
- KataContainers - k8s but with VM isolation
- stow - software management by symlinks
- habitat - similar philosophy as nix but not as clean and functional and almost like Arch PKGBUILD but with more infrastructure around it
- JTAG - debug all the things
- in-circuit emulators (ICEs) - hardware-based debuggers
- polarized light sources - easier to see things under the bi/trinocular microscope
- DNSSEC+DANE - It's half-assed deployed but there's a lack of end-user UX
- wais - search before gopher
- afs - distributed fs
- discard protocol - basically, a network-based /dev/null
- humans.txt - Not around as much as it was
- makeheaders - Auto-generated C/C++ headers
- man page generators - ronn and help2man
- checkinstall - The automatic software package creator
- bashdb and zshdb
- crystal - Compiled Ruby-ish
- forth - Powered the FreeBSD bootloader menu for many years and word processors (typewriter-like almost computers)
- ocaml - The best ML, used by Jane Street and Xen
- pony - A language built around an arguably better GC than Azul's C4 with arguably stronger sharing semantics than Rust
- prolog - Erlang's grandpa
- rpython - PyPy's recompiler-compiler
- pax - POSIX archives
- shar - shell archives - Self-extracting archives that look like scripts at the beginning
- surfraw - Shell Users' Revolutionary Front Rage Against the Web - founded by Julian Assange
- step-ca - A Go-based PKI server
- dmraid - Because it works
- X10 - Before WiFi and IoT, there was the Firecracker: a parasitic power serial port RF outlet controller
- FreeBSD - It's not unknown or obscure per se, but it powers many important things in the civilized world without getting much credit
- :CueCat - A dotcom era barcode reader that was given away
- Xen - If you need to run a VPS but can't ju$tify u$ing VMware
- KataContainers - k8s but with VM isolation
- stow - software management by symlinks
- habitat - similar philosophy as nix but not as clean and functional and almost like Arch PKGBUILD but with more infrastructure around it
- JTAG - debug all the things
- in-circuit emulators (ICEs) - hardware-based debuggers
- polarized light sources - easier to see things under the bi/trinocular microscope