Lightweight non-interactive sh(1)-like scripting language

https://www.skarnet.org/software/execline/

Port of Adobe XMP SDK to work on UNIX

http://libopenraw.freedesktop.org/wiki/Exempi

Full-featured exFAT FS implementation as a FUSE module

https://github.com/relan/exfat

Utilities to create, check, label and dump exFAT filesystem

https://github.com/relan/exfat

Command line utility to read and manipulate EXIF data

http://sourceforge.net/projects/libexif/

Exif, IPTC, and XMP metadata manipulation library and tools

https://www.exiv2.org/

Geometric sans serif font with a technological feel

http://www.ndiscovered.com/

XML 1.0 parser written in C

https://github.com/libexpat/libexpat

Sophisticated scripter based on Tcl/Tk

http://expect.sourceforge.net

Application to track your expense under GNUstep

http://www.eskimo.com/~pburns/Expense/

FUSE module to mount ext2, ext3 and ext4 with read write support

https://github.com/alperakcan/fuse-ext2

Partition-selectable boot loader for IBM-PC/AT compatibles

http://extipl.sourceforge.jp/

Tool for extracting and creating optimised Xbox ISO images

http://sourceforge.net/projects/extract-xiso/

Modern, maintained replacement for ls

https://eza.rocks/

Framework to easily create, manipulate, and run BSD jails

http://erdgeist.org/arts/software/ezjail/

Fortran-to-C converter and its run-time libraries

http://www.netlib.org/

MPEG-2 and MPEG-4 AAC audio encoder

https://www.audiocoding.com/

MPEG-2 and MPEG-4 AAC audio decoder

https://github.com/knik0/faad2

Visual mail, user, and print face server

http://faces.sourceforge.net/

Functional Constraint Library

http://www.recherche.enac.fr/log/facile/

Simulate the root user behaviour

http://freshmeat.net/projects/fakeroot

File alteration monitor

http://oss.sgi.com/projects/fam/

Programming font, designed with functionality in mind

https://fontlibrary.org/en/font/fantasque-sans-mono

Serif based on the work of a famous Czech-American type designer

https://www.theleagueofmoveabletype.com/fanwood

Standard set of Unicode Persian fonts

http://www.farsiweb.ir/wiki/Persian_fonts

Collection of GStreamer modules and libraries for videoconferencing

https://www.freedesktop.org/wiki/Software/Farstream/

Fast and exact C++ number parsing library

https://github.com/fastfloat/fast_float

Like neofetch, but much faster because written in C

https://github.com/fastfetch-cli/fastfetch

version of JDK's `jar' command written entirely in C

http://fastjar.sourceforge.net/

Accuracy-focused XAudio reimplementation

https://fna-xna.github.io/

Functional programming language for realtime audio signal processing

https://faust.grame.fr/

FastCGI Development Kit

http://www.fastcgi.com/

Flexible Input Method Framework

https://fcitx-im.org/wiki/Fcitx

Chewing support for Fcitx

https://fcitx-im.org/wiki/Fcitx

Cloud-based Pinyin module for Fcitx

https://fcitx-im.org/wiki/Fcitx

Fcitx IM framework configuration tool

https://fcitx-im.org/wiki/Fcitx

Libpinyin support for Fcitx

https://fcitx-im.org/wiki/Fcitx

Fcitx support for Qt5

https://github.com/fcitx/fcitx-qt5

New implementation of the Fcitx IME framework

https://github.com/fcitx/fcitx5

Pinyin and table input method support for Fcitx5

https://github.com/fcitx/fcitx5-chinese-addons

Lua support for Fcitx5

https://github.com/fcitx/fcitx5-lua

Fcitx support for Qt (qt5)

https://github.com/fcitx/fcitx5-qt

Fcitx support for Qt (common files)

https://github.com/fcitx/fcitx5-qt

Other table support for Fcitx5

https://github.com/fcitx/fcitx5-table-other

CUI-based file and directory management tool

https://hp.vector.co.jp/authors/VA012337/soft/fd/

Port of the Fraunhofer FDK AAC Codec Library

https://sourceforge.net/projects/opencore-amr/

FDM Material database for 3D printers

https://github.com/Ultimaker/fdm_materials

Haptic/visual/audio feedback for GNOME

https://source.puri.sm/Librem5/feedbackd

Image viewer that utilizes Imlib2

https://feh.finalrewind.org/

Batch mail retrieval utility for IMAP/POP3/ETRN/ODMR

https://www.fetchmail.info/