It was a special in-person, weekend long event, where you could get Eevee (a pokémon) with a Sydney background.
https://pokemongolive.com/events/citysafari/sydney
It was pretty much the first in-person pokémon go event in Australia so it was very exciting

There were 7 different "zones" in Sydney to visit, each with 8 eevees in specific locations i.e. darling Harbour, Barangaroo, etc etc
It was basically getting you to visit a wide range of Sydney landmarks and whatnot
The items I missed were from those locations with the eevees: you could save a copy of that location into your account. The event has ended, but they leave the pokéstops (locations) there. Even though I went to all of them back in December, I forgot to save 8 of the pokéstops...