This is available on Drupal CVS
The helpdesk source code itself is now available on drupal in the CVS Contrib repository.
Preliminary design info is available on FGM's blog
Content-oriented classes share similar methods:
These are:
helpdeskObject helpdeskContract helpdeskEvent helpdeskTicket helpdeskFollowup helpdeskTimeInfo
See the PHPDocumentor doc.
In short:
The HD HD Techs and ATTENDANT have no direct implementation.