Ultra Unlock: Week 3
Unusual Pokémon will be appearing in the wild during this week. Noteworthy opponents are coming to raids, too. During this week, you may also be able to add some Pokémon to your Kanto Pokédex that previously eluded you in your part of the world. (Japanese version of the announcement notes Shiny Pokémon).
It will also include a special bonus. More details will become available on August 20.