Understanding AutoCAD plugin files by Example

I am interested in developing an AutoCAD plugin and am trying to understand the relationships between several different types of AutoCAD plugin files:

• Managed DLLs that ship with AutoCAD plugins
• ARX files that ship with AutoCAD plugins
• CUIX files that ship with AutoCAD plugins

From what I can tell these three files are all inter-related and work together to initialize and load a plugin, I’m just not seeing the forest through the trees as to what information each file type contains, which files loads or depends on the others, etc.

It sounds like a plugin’s core functionality is supposed to go inside the ARX file, and written in C++ and compiled for the native/target platform.

It also sounds like, at startup, AutoCAD loads its plugin DLLs, which are all managed .NET libraries (typically written in C#), and in turn they invoke their native/compiled respective ARX files. As to where the CUIX file comes into play, I still have no idea.

Can anyone help explain the relationships & dependencies of these files, and what types of code/logic/data goes inside of them? Thanks in advance!