This is part of the quest “Out of Fire”. The perimeter is guarded by heavily armed raiders called The Forged with molotovs and flamers. There are some food in the trailer outside and mattresses by the entrance where you can rest after the battle. There’s also a Cooking Station outside.
In inside the building, there’s a terminal-locked door to the SE, by the upper level. The terminal beside is Advanced as well. To the NE corner of the 2nd level is a protectron you can activate by hacking the Novice terminal beside it. However, this door can be unlocked easily from the other side.
There’s a couple of ammo boxes in the NW corner of the second half of the building and a first-aid kit on the wall above the boxes. IN the upper level, there’s a large room with the armor and weapon workbenches. Right before the exit to the Saugus Blast Surface area, you can find a Power Armor station.
In the Saugus Blast Surface, if you missed it during the quest, you can find the Explosive Bobblehead beside the steamer trunk in the upper walkway. Below that steamer trunk is another edition of Picket Fences so make sure to pick up since it blends well with the catwalk.
The rooftop of the building doesn’t have anything to offer aside from the lootable bodies of the Forged you killed earlier.