Intact Structures in XCOM 2 are Resistance Rumors you can investigate which lead to rewards. They are alerted to you from contacted Locations.
Intact Structures Information
They will have a time to investigate specified as well as the rewards.
Flavor text from a successful investigation: Many of the buildings in this area are still intact, so we broadcasted a wide area signal in the hopes of contacting possible survivors. A small group of people cautiously emerged from an old warehouse and expressed interest in joining the Resistance.
- Rookie Soldier