This is an addon that can be used by the Lua Language Server.
It provides type definitions and documentation for the Lua interface implemented by MAME.
You must be using the Lua Language Server in order to use these type definitions effectively. Until they are added to the official LLS-Addons, you may download this repository and then add the library/ directory to your LuaLS configuration file's workspace.library.
TODO: clean up text formatting; clear up unknown types; add links where appropriate