Distributed, RESTful search and analytics engine

https://www.elastic.co/

Functional, meta-programming aware language built on top of Erlang VM

https://elixir-lang.org/

Elvish = Expressive Programming Language + Versatile Interactive Shell

https://elv.sh/

Enhanced Motif WM fork with multi-monitor and utf-8 support

https://fastestcode.org/emwm.html

Detect encoding of text files

http://gitorious.org/enca

Encrypted pass-through FUSE filesystem

http://www.arg0.net/encfs

Dictionary/spellchecking framework

https://rrthomas.github.io/enchant/

High-performance, zero maintenance encrypted DNS proxy

https://github.com/jedisct1/encrypted-dns-server

Runs arbitrary commands when files change

https://eradman.com/entrproject

Shell helper that automatically sets and unsets environment variables

https://github.com/wojas/envy

Functional programming language from Ericsson

https://www.erlang.org/

IDNA implementation in pure Erlang

https://github.com/benoitc/erlang-idna

Functional programming language from Ericsson

https://www.erlang.org/

Functional programming language from Ericsson

https://www.erlang.org/

Functional programming language from Ericsson

https://www.erlang.org/

Functional programming language from Ericsson

https://www.erlang.org/

Compatibility library for unicode_util from Erlang R20

https://github.com/benoitc/unicode_util_compat

Extensible shell, derived from plan9's rc

http://wryun.github.io/es-shell/

Extremely fast JavaScript bundler and minifier

https://esbuild.github.io/

Sound library for enlightenment package

http://www.tux.org/~ricdude/EsounD.html

Software speech synthesizer

https://github.com/espeak-ng/espeak-ng/

Input event device header files

Modern replacement for ls

https://the.exa.website/

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

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

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

Exif, IPTC, and XMP metadata manipulation library and tools

https://www.exiv2.org/

XML 1.0 parser written in C

https://github.com/libexpat/libexpat

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/

Modern, maintained replacement for ls

https://eza.rocks/

MPEG-2 and MPEG-4 AAC audio decoder

https://github.com/knik0/faad2

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

Fast and exact C++ number parsing library

https://github.com/fastfloat/fast_float

Simple library for font loading and glyph rasterization

https://codeberg.org/dnkl/fcft

FastCGI Development Kit

https://github.com/FastCGI-Archives/fcgi2

FDM Material database for 3D printers

https://github.com/Ultimaker/fdm_materials

Finite element analysis program (personal version)

http://projects.ce.berkeley.edu/feap/feappv/

Realtime audio/video encoder/converter and streaming server (without x11)

https://ffmpeg.org/

Realtime audio/video encoder/converter and streaming server (legacy 4.* series)

https://ffmpeg.org/

FFmpeg version of Nvidia Codec SDK headers

https://github.com/FFmpeg/nv-codec-headers

Easy to use graphical editor for electronics

https://darwinne.github.io/FidoCadJ/index.html

Narrow monospaced fonts

https://fontlibrary.org/en/font/fifteen

Flexible IO tester

https://git.kernel.dk/cgit/fio/

Sans-serif, monospaced, and code typeface for small screens

https://bboxtype.com/typefaces/FiraSans/

Monospaced font with programming ligatures derived from Fira

https://github.com/tonsky/FiraCode

Expanded version of Fira Sans with support for additional languages

https://bboxtype.com/typefaces/FiraGO/

Firehol ip list downloader

http://iplists.firehol.org/

Memory efficient serialization library

https://google.github.io/flatbuffers/