SVN access
ZPTDebugger is also available from Plone Collective repository
Linux
If you are using Linux machine go to your Zope's Products directory and execute command:svn co https://svn.plone.org/svn/collective/ZPTDebugger/trunk ZPTDebugger
Windows
For Windows the easiest way is to use TortoiseSVN. Then just right-click your mouse in Zope's Products folder, select SVNCheckout and insert URL of repository and Checkout directory like on image below.