When I want to open the example file I get this message from winpdb:
Failed to load source file 'c:\program files\sublime text 3 portable beta\data\installed packages\plugin debugger.sublime-package\plugin debugger.sublime-package' from debuggee. You may continue to debug, but you will not see source lines from this file.
I suppose it's because the file is in the zip archive and winpdb can't open it. You probably have to copy it elsewhere before opening it with winpdb or add a
.no-sublime-package file to your repo so that Package Control will unextract it.
Similarly, the menu entry in "Preferences > Package Settings > Plugin Debugger > view debug_example.py" does not work, even though it should even for zipped packages.
Only later I found out that the file doesn't exist in the first place.