In XLL+ we've added support for hidden regions.
Almost all of the generated code is now surrounded by
#pragma region blocks.
This means that almost all of the implementation code for each add-in can be hidden,
and you need only see the code that is interesting - the function signature
and your own code.
And, unless you click on the "+" symbol to expand the code, the XLL+ tool-kit will ensure that the implementation stays hidden, and out of your way.
Some of the more complicated add-in functions, particularly asynchronous functions, can have over a hundred lines of implementation code. It is much easier to maintain your own code if all of this detail is hidden.
See Hidden regions in the User Guide for more details.