The Mod DLL Project is a project that revolves over a client(Mod.exe) and a DLL that is loaded with functions that the client will use(ModDLL.dll & lua53.dll).
The basics of Mod DLL
The relationship between Mod.exe and ModDLL.exe(and lua53.dll) is that Mod.exe "accesses" fuctions inside of ModDLL.dll(which utilizes lua53.dll) providing a pseudo terminal. This allows the user to use Mod.exe to do various commands based on the release of the DLL or the programmer that made the DLL themselves.
Why its useful
TL;DR any programmer can go to the github and compile their own version of the DLL with their own code for others to use. Programmers are able to go to the Githubdownload the source code, add their own revisions, and compile thier own custom DLL with their custom functions and code.