How do bounty hunter tracking fobs/beacons work in “The Mandalorian?”

Question

So the Mandalorian — and others in the bounty hunter guild — get work by agreeing to take on a bounty. And that seems to involve meeting with a middle man (such as Greef Carga as played by Carl Weathers) and getting some kind of tracking fob/beacon.

But how the heck does that even work? How can it even track a specific person? Is there some kind of genetic signature involved?

For example, in episode 3 of The Mandalorian when the Mandalorian rescues that Yoda baby, suddenly everyone’s beacon for that Yoda baby starts bleeping like crazy. How did that work? I mean how do those beacons know that the bounty target is no longer in custody? What changed between the baby Yoda’s captivity with Imperial agents to the Baby Yoda being carried away by the Mandalorian?

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Looking for in-universe, canonical explanations; not armchair speculation and theories. If none (currently) exist, legends explanation would suffice. Regardless, please provide references and context.

Answer 1

Per the Star Wars Book, The tracking fob contains a description of the target's 'biometric data' and 'biographical details, known as a chain code. The tracking fob uses a short-range sensor to locate individuals with that precise profile.

The puck or posting lists the details of the bounty: the amount offered, the circumstances (or crimes) that warranted the bounty, the operational jurisdiction allowed for pursuit, and specific conditions required to collect (for example, “dead or alive.”) If the bounty hunter agrees to take on the assignment, he or she gets access to the target’s chain code—an identification marker that describes certain biographical information. This code drives the parameters of a tracking fob, a short-range sensor attuned to this biometric data. Upon the capture and delivery of a target, the Guild operative runs a sensor check on the body and compares it to the chain code data on the fob, confirming the identification of the acquisition.

It's not clear what biometrics exists in the Star Wars universe that can be sensed at distance, but in the pilot episode of The Mandlorian, we learn that the final four digits correspond to the target's precise age. This is (apparently) sufficient to track them, although we can assume that Mando's issue with this is that he'll have to wade through a whole passel of false positives if the target isn't at or near to the last location.

Din Djarin: What's the chain code?

Client: We can only provide the last four digits.

Din Djarin: Their age? That's all you can give me?

Client: Yes. They're 50 years old. We can also give you last reported positional data. Between that and the fob, a man of your skill should make short work of this.