Lua is a programming language that was developed specifically for expanding applications and to be used in embedded systems. So, many applications support Lua as their plugin programming language of choice. Wireshark is no exception to this.
To learn more about Lua, you can go to https://www.lua.org/. You can also go through the various books on Lua programming published by Packt.
You can also go on the Lua website and refer to their documentation section, where you'll find a link https://www.lua.org/pil/ that covers Programming in Lua:
You can see a free book that's available for you to learn programming in Lua. Additionally, ...
