By providing a standard way to describe data recordings, SigMF facilitates the sharing of data, prevents the "bitrot" of datasets wherein details of the capture are lost over time, and makes it possible for different tools to operate on the same dataset, thus enabling data portability between tools and workflows.

Implementations of the the standard are available for Python, C++ and GNU Radio.

Recently a DCF77 receiver and decoder program based on Python and GNU Radio has been uploaded to GitHub
https://github.com/henningM1r/gr_DCF77_Receiver
by henningM1r. It includes a simulator written in Python so you can simulate your own DCF77 signal for testing the receiver too.

Currently the decoder has been tested to work with an Airspy HF+ Discovery SDR, but it should work with any SDR capable of receiver 77.5 kHz if the GNU Radio source block is changed out.

GNU poke is a new interactive editor for binary data. Not limited to editing basic entities such as bits and bytes, it provides a full-fledged procedural, interactive programming language designed to describe data structures and to operate on them.
Home page: http://www.jemarch.net/poke

Found via a link on Ekaitz's blog https://ekaitz.elenq.tech/bootstrapGcc2.html

Found http://www.maizure.org/projects/decoded-gnu-coreutils/index.html via https://www.gnu.org/software/coreutils/#source
Recommended reading: http://www.maizure.org/projects/printf/index.html

Settings for emerge, smerge sounds interesting too.

It offers nearly GNU/Linux Emacs experience in Windows with minimum configuration efforts. A set of additional GNU command-line and development tools is available through the network installer. Includes commonly used POSIX utilities such as diff, grep, aspell.
Optionally, a number of Lisp implementations can be installed.

Installing the Guix package manager on Android, requires root access.
Note that "Guix complains when /gnu or /gnu/store is a symlink".

64-bit Windows build of Emacs 26.0.91. DLLs included.
Patched with ImageMagick 7 support. Binaries and libs included.
PDF-TOOLS (epdfinfo.exe) included.
Features[1]: "XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS LCMS2"
Optimized clean build. Options[2]: "--without-compress-install --without-dbus --with-modules 'CFLAGS= -O2 -pipe -g3'"

Built and tested on a clean Windows 10 system.
addpm modified to not create/update any registry HOME entries. It only creates shortcuts as it should.

A GNU implementation of the Secure Shell protocols

lsh is a free implementation (in the GNU sense) of the ssh version 2 protocol, standardised by the IETF SECSH working group.