Freedesktop.org backend for WPE WebKit

https://wpewebkit.org

pop3 server for retrieval of remote mail on a UNIX system

http://www.bsdnexus.com/wpop3d/

Upload files or directories to FTP server with resume support

http://wput.sourceforge.net/

GNU GPL-licensed font set covering CJK and other Unicode characters

http://wqy.sourceforge.net/en/

Modern HTTP benchmarking tool

https://github.com/wg/wrk

Command-line file transfer tool over wireguard

https://github.com/coder/wush

Command-line utility for stalking users

https://www.cs.swarthmore.edu/~finney/proj/wuzzah/

Library and executables to access Microsoft Word files

http://wvware.sourceforge.net/

Library providing routines to access Microsoft Word files

http://wvware.sourceforge.net/

Biographical dictionary (EPWING V1 format)

http://openlab.ring.gr.jp/edict/fpw/

The wxWidgets GUI toolkit with GTK+ bindings

http://www.wxwidgets.org/

GUI toolkit (wxWidgets) with GTK+3 bindings

https://www.wxwidgets.org/

Modular FTP server configurable online using SITE commands

http://www.wzdftpd.net/

X11 server performance test program

VNC server for use with real X displays

http://www.karlrunge.com/x11vnc/

Front-end for encoding H.264/MPEG-4 AVC video

http://www.videolan.org/x264.html

H.265/High Efficiency Video Coding (HEVC) format

http://www.x265.org/

Program to link multiple X and VNC servers together

http://fredrik.hubbe.net/x2vnc.html

A program to link multiple X servers together

https://github.com/dottedmag/x2x

Two-pass cross-assembler for MOS 6502 and compatible CPUs

http://www.floodgap.com/retrotech/xa/

Apache XSLT processor for transforming XML documents

http://xml.apache.org/xalan-j/

X based alarm clock

https://ftp.gwdg.de/pub/x11/x.org/contrib/utilities/xalarm.README

Play most popular animation formats and show pictures

http://smurfland.cit.buffalo.edu/xanim/home.html

Bindings allowing Xapian to be used from various programming languages

https://xapian.org/

Probabilistic text search database engine

https://xapian.org/

Cross-desktop libraries and common resources

https://github.com/linuxmint/xapp

Set of symbolic icons for Gtk applications and projects

https://github.com/xapp-project/xapp-symbolic-icons

OpenDarwin XML eXtensible ARchiver

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

X authority file utility

TV viewing application and a few TV utilities

https://linuxtv.org/

Program to adjust backlight brightness

Motif-based widget which displays a grid of cells as a spreadsheet

http://xbae.sourceforge.net/

Mailbox flag for X

X.Org bitmaps data

Brightness and gamma correction through the X server

http://disjunkt.com/xbrightness/

High-performance low-overhead BitTorrent tracker

https://xbtt.sourceforge.net/

Replacement for xbiff that handles multiple mail files

Scientific calculator for X

Calendar with a notebook for X11 (internationalized version)

Tool for managing x11 cut-buffers

http://oldhome.schmorp.de/marc/xcb.html

Input method development support for XCB

https://github.com/fcitx/xcb-imdkit

The X protocol C-language Binding (XCB) protocol

http://xcb.freedesktop.org/

Module with libxcb/libX11 extension/replacement libraries

http://xcb.freedesktop.org/

XCB cursor library

http://xcb.freedesktop.org/

Pretty-print XCB codes

https://xcb.freedesktop.org/

Port of Xlib's XImage and XShmImage functions

http://xcb.freedesktop.org/

Standard X key constants and conversion to/from keycodes

http://xcb.freedesktop.org/

Convenience functions for the Render extension

http://xcb.freedesktop.org/

Framework for window manager implementation

http://xcb.freedesktop.org/

XCB utility functions for the X resource manager

https://github.com/Airblader/xcb-util-xrm