Generic Colouriser

http://kassiopeia.juls.savba.sk/~garabik/software/grc.html

Framework focused on making media discovery and browsing

https://wiki.gnome.org/Grilo

Notification system compatible with Growl

http://mattn.github.com/growl-for-linux/

HTTP/2-based RPC framework

https://grpc.io/ https://github.com/grpc/grpc

Media applications framework

https://gstreamer.freedesktop.org/

Gstreamer element validation suite

https://gstreamer.freedesktop.org/

Theme engine for the GTK+-2.0 toolkit

https://www.gtk.org/

Gtk-update-icon-cache utility from the Gtk+ toolkit

https://www.gtk.org/

Graphical UI toolkit (GTK3 library)

https://www.gtk.org/

C++ wrapper for Gtk+

https://www.gtkmm.org/

Widget that adds syntax highlighting to GtkTextView

GNU Ubiquitous Intelligent Language for Extension

http://www.gnu.org/software/guile/

Pure-C HTML5 parser

https://github.com/google/gumbo-parser

Command line tool of Yahoo! Dictionary

https://github.com/iamgyz/gydict

Typeface designed for source code

https://sourcefoundry.org/hack/

Library of matchers for building test expressions

https://hamcrest.org/

HAMMER2 file system for FreeBSD (experimental write support)

https://github.com/kusumi/freebsd_hammer2

CJK Mincho-typeface developed by Hanazono University

http://fonts.jp/hanazono/

Advanced CPU-based password recovery utility

https://hashcat.net/hashcat/

Hierarchical Data Format library (from NCSA) (latest)

https://www.hdfgroup.org/

Portable and enhanced troff, nroff, and related utilities

https://n-t-roff.github.io/heirloom/doctools.html

Monospaced font for programmers by a programmer

https://pcaro.es/p/hermit/

Tiny program that sends some load to a web application

https://github.com/rakyll/hey

HFSExplorer read Mac-formatted harddisks and disk images

https://www.catacombae.org/hfsexplorer/

High-color icon theme shell from the FreeDesktop project

https://www.freedesktop.org/Standards/icon-theme-spec

Library to access USB HID-class devices

https://github.com/libusb/hidapi

Solver for large scale sparse linear programming (LP) problems

https://github.com/ERGO-Code/HiGHS

Performance-portable, length-agnostic SIMD with runtime dispatch

https://github.com/google/highway

Minimalistic C client library for the Redis database

https://github.com/redis/hiredis

Hyper NIKKI System, a CGI system for Electric Diary Interchange

http://www.h14m.org/

Split files into encrypted fragments

https://github.com/jesseduffield/horcrux

IEEE 802.11 AP, IEEE 802.1X/WPA/WPA2/EAP/RADIUS Authenticator

https://w1.fi/hostapd/

Converts HTML documents into plain text

https://gitlab.com/grobian/html2text

Better top(1) - interactive process viewer

https://htop.dev/

HTTP request/response parser written in C

https://github.com/nodejs/http-parser

Tool for measuring webserver performance

https://github.com/httperf/httperf

Improved spell-checker for Hungarian and other languages

https://hunspell.github.io/

Probe for hardware, check operability, and finding drivers

https://bsd-hardware.info/

Database of IDs used in PCI, PNP and USB devices

https://github.com/vcrhonek/hwdata

Command line tool to display CPU temp and battery infos

https://BSDforge.com/projects/sysutils/hwstat/

Program to generate a cross-referenced HTML mail archive

http://www.hypermail-project.org

Wayland protocol extensions for Hyprland

https://github.com/hyprwm/hyprland-protocols

Official implementation library for the hypr config language

https://wiki.hypr.land/Hypr-Ecosystem/hyprlang/

Hyprland utilities library used across the ecosystem

https://github.com/hyprwm/hyprutils

Hyprland implementation of wayland-scanner

https://github.com/hyprwm/hyprwayland-scanner

Fast and consistent wire protocol for IPC

https://github.com/hyprwm/hyprwire

Heterogeneous set of I2C tools

https://i2c.wiki.kernel.org/index.php/I2C_Tools

Thermal and C-state reporting utility for Intel Core CPUs

https://github.com/DimitryAndric/i7z

Intelligent Input Bus for Unix-like systems

https://github.com/ibus/ibus

PinYin engine for IBus

http://code.google.com/p/ibus