How to unlock: Speak with Suvi [Tempest].
Here you can find the guide for Excess Baggage quest. This is a quest in Heleus (assignment), in Mass Effect: Andromeda game. The quest takes place entirely on Tempest. It is about the titular excess baggage - you must determine where the unknown baggage is and, when you find it, decide on what to do with it.
Unlocking the quest
This quest should be unlocked during one of your conversations with Suvi on Tempest. From her you learn about an unidentified big baggage and you are asked to find it.
Scan Tempest's rooms to find the anomaly
The anomaly that you must find is behind the wall in a small armory, presented on the picture above. Said armory is on the lowest deck of the ship in its south-east part. You must use your scanner to find it.
After identifying the anomaly you must go to the bridge and speak with Kallo. Listen to the conversation and to the audio recording. The last thing that you must do is to decide what you want to do with the found mech. The choice ends this quest.
Rewards for finishing the quest: XP, Andromeda Viability Points.