It actually is a thing, although indirectly in a hacky way! If you push keys from GitHub secret scanning partners to a public repo or a gist, they get sent to the partner who (usually) instantly revoke them. So if you want to help someone, just make a public gist with the key and delete it like 15 seconds later, it'll be enough.
https://docs.github.com/en/code-security/reference/secret-se... has a table with the active partners