Temporary expedition has its own thematic Task List, which can be opened by tapping on this icon:

  The Task List contains a list of all optional tasks in the temporary expedition, the fulfillment of which will not affect the story, but will bring nice rewards.
  

  You get golden tokens for completing these tasks. At the bottom of the Task List screen, you can see a gift bar, which you'll get after collecting a sufficient number of tokens. Each next gift in the list costs more tokens but contains a more valuable reward.

If you have tokens left after the end of a temporary expedition, they will be exchanged for energy for the expedition.