How does the secret sniffer work?

[Omega]

I got the secret sniffer upgrade but it doesn't seem to do anything how does it wok?

[Chainsaw-thecat]

There is a small, gray, question mark at the bottom right of the tracker. It shakes and turns white when you are close to one of the items it lists.

[Omega]

thanks

[avarbence]

firstly i found it i think but nothing happened