9front is a fork of the Plan 9 operating system.

Kobuk ist ein Medienwatchblog von Studierenden der Lehrveranstaltung „Multimedia-Journalismus“ am Publizistikinstitut der Uni Wien, unter der Leitung von Helge Fahrnberger und Yilmaz Gülüm, sowie ständiger Autoren wie Hans Kirchmeyr.

Baudline is a time-frequency browser designed for scientific visualization of the spectral domain.  Signal analysis is performed by Fourier, correlation, and raster transforms that create colorful spectrograms with vibrant detail.  Conduct test and measurement experiments with the built in function generator, or play back audio files with a multitude of effects and filters.  The baudline signal analyzer combines fast digital signal processing, versatile high speed displays, and continuous capture tools for hunting down and studying elusive signal characteristics.

Description of pluggable authentication modules for Linux, from 1997.

Code can be found on https://github.com/froggey/Mezzano
Documentation is sparse, but it appears to target x86.

NEUES, WISSENSWERTES UND HINTERGRÜNDE AUS DER WISSENSCHAFT.
AUS ÖSTERREICH; MIT OFFENEM BLICK IN DIE WELT.

A tool for literate programming in Common Lisp. Unlike noweb https://www.cs.tufts.edu/~nr/noweb or CLWEB http://www.cs.brandeis.edu/~plotnick/clweb, it does not have a tangling (code extraction) phase, so interactive development is possible.

USB storage devices with hardware encryption and keypad. Capacities range from 4 GB to 6 TB.

Executable Wiki: non-linear, text-based shell. I am not explaining this well, take a look at the screencasts.

eCryptfs is a POSIX-compliant enterprise cryptographic stacked filesystem for Linux. eCryptfs stores cryptographic metadata in the header of each file, so that encrypted files can be copied between hosts; the file will be decrypted with the proper key in the Linux kernel keyring. There is no need to keep track of any additional information aside from what is already in the encrypted file itself. You may think of eCryptfs as a sort of "gnupg as a filesystem".