6.36 OSPF Reliable Conditional Default Routing

Hi,

i don't know with this.

Rack1R4#sh run | i ip route
track 1 ip route 204.12.1.0 255.255.255.0 reachability
ip route 169.254.0.1 255.255.255.255 Null0 track 1

what is mean of this configuration?

Thnk's