Unfortunately, nobody else seems to either, which is why my comment is getting downvoted.
"Why is this a problem?" say people when the publishing of a private key is inherently the wrong thing to do, and will always lead to a bad consequence.
It doesn't matter who's key it is, how it was generated, how it was obtained, etc...
The purpose of private keys is to be kept secret. A published private key by definition is worthless. That will have a consequence. Either it'll be make-believe fairytale security, or someone else getting into your product, or what happened here: the third party who's keys were stolen changed the locks.
Meanwhile I'm at -4 and clocking down because people struggle to understand how keys and locks work, never mind cryptography.
> A published private key by definition is worthless.
If I publish the AACS _private_ key, is it now worthless?
Public-private key pairs only work if the private key is secret. If it’s not secret it doesn’t work.
This is a simple fact of how cryptography works. Or passwords, keys, or any secret like an API key, etc…
If you publish such things on GitHub, they instantly become “not what you’ve labelled it as”.
So you admit it's not completely worthless at that point only for specific use cases.
So we've established that a "private key" that is no longer private may still have uses to some people, it is not wholly "worthless."
Do you want to revise your earlier statement about the private key in the repo in question? Is it "worthless"? Is it a security problem? Do you know what that key is being used for?