The name of the file is sent to some Perl code.

The Perl code launches a Client/Server Debugger.

The Perl code steps through the user code.

The debugger captures all of the data using PadWalker.

The data is all sent back to the plugin's Clojurescript code.

The Clojurescript code maintains a history of the entire execution trace.

The editor is updated to show the last state.