So I had something similar happen to the OP a couple of days ago. I'm on friendly terms with a competing codebase's developer and have confirmed the following with them, both mine and it are closed source and hosted on github.
Halfway through building something I was given a block of code by copilot, which contained a copyright line with my competitors name, company number and email address.
Those details have never, ever been published in a public repository.
So I had something similar happen to the OP a couple of days ago. I'm on friendly terms with a competing codebase's developer and have confirmed the following with them, both mine and it are closed source and hosted on github.
Halfway through building something I was given a block of code by copilot, which contained a copyright line with my competitors name, company number and email address.
Those details have never, ever been published in a public repository.
How did that happen?