Find useful information and items which will help to understand what is going on in the city. There will be loot of various rareness and it will spawn at locations at different places, in containers. Specific loot will spawn at specific locations (facility, center of the city). Rare loot items will spawn at places, where no one looked, (hard to access places, closed rooms and so on). For each raid, lootable items are being generated over again.
Story-essential loot will always switch the spawn locations and discovery conditions (e.g. door access codes). Also there will be rare or even unique items in game - weapons, equipment, etc - with a low chance of finding.