How do I "auto" generate Off Mesh Links?

Looking through the docs I'm having trouble finding anything on this. In the Cave scene of the "NavMeshExample", there is a gameobject called "4_Autogenerated_Links" and it appears to have connected two planes (the blue soldier jumps over this gap). If I select the "4_Autogenerated_Links" gameobject and go into the "Navigation" tab, I can click "Clear" and then "Bake" and the links are generated again. If I hit "Reset" and then "Bake" the links are no longer generated.

Anyone know how to auto generate Off Mesh Links?

Thanks!