We have put together much more detail on the various debugging options available to plugin developers on a page discussing how to set up a plugin development environment.
Setting up an Indigo Plugin Development Environment
Debugging
The debugging section also describes a new EXPERIMENTAL (as of right now) method to do real-time debugging of a plugin running on an Indigo server over IP (i.e., running the PyCharm debugger on machine other than the one running the Indigo server.) Although experimental, it has been running very stably in testing.
We'll continue to update the wiki page as we learn more about what additional information folks need.