Q: What is "stingray identity" in my sign in log?

Hi

I believe stingray identities are associated while online games...maybe you have signed in previously to an online gaming site?

A Stingrays is a law enforcement surveillance device.

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Etrecheck – System Information

But it's not something that is installed on a Mac.  It's used by the police to simulate cell towers to track cell phones. Don't see how it would be that here.  More likely the gaming side.