Similar to Lua

Illumos

Iperf

IPodLinux

Iptables

Irssi

Kernel-based Virtual Machine

Kitty (terminal emulator)

LADSPA

Leafpad

Libavcodec

Libjpeg

Libpng

LibreSSL

Librsvg

Libvirt

Libwww

Lighttpd

Linux-libre

Linux kernel

LIRC

Lis (linear algebra library)

MDB Tools

Mesa (computer graphics)

Metacity

TinySPARQL

MicroEMACS

MicroPython

MiKTeX