The Trade Drone is the Advent's trade ship.
It has its own ability that can be eventually researched, Karmic Retribution that puts bounty on the faction that destroys it. This ability is useless against Pirates, Local Militia, and if you are on a custom map, neutral colonies. If this ship's Trade Port activates "Resource Focus" it will return and dock as usual, but it will not leave until the ability is disabled again. This means that presumably this ship is not manned and that, like the Advent Strikecraft and the Assembly Drone it is likely controlled remotely.
While in a direct fight the Trade Drone is worthless. Karmic Retribution (should pirates be enabled) can help a losing faction by forcing some of their fleet or resources away toward dealing with the Pirate Assault (should they not pay off the bounty). Resource focus is generally seen as an unviable ability as it is best to earn credits and pay for the resources you need instead, so generally it is best to skip this upgrade. Also, like all trade ships this ship can be scuttled for zero Resources, if you want to keep your enemy from getting your trade credits or you just feel like it.
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