Moshe Weitzman has been a consistent contributor to Drupal core and Contrib since November 2001 (i.e. before drupal.org was born). As such, he has pretty much touched the whole core code. He maintains the user.module, the bootstrap code, the Devel project, and Drush, the Drupal shell. He is also a member of the Security team and a Permanent Member of the Drupal Association.