If you were to run find / -iname *.prefPane on your freshly installed copy of Leopard, you might notice this show up in the results:

/System/Library/CoreServices/Archive Utility.app/Contents/Resources/Archives.prefPane

Installing this preference pane allows you to change settings relating to archive creation and expansion handled by Archive Utility (formerly BOMArchiveHelper).

This joins the other known hidden prefPane introduced in 10.4, DiskImages.prefPane (hat tip to Mac OS X Hints for beating me to the punch by a year and a half).