Could be, or maybe that just discovered the GitHub private repo leak issue that was discussed a few months back:
And if you leak credentials, you'd just have to rotate them. Taking the repo offline would probably be too late anyway and causes a major mess, so not something I could recommend for popular repos
[I work for Elastic]
Since we don't maintain private forks for the Elasticsearch repository (maybe for someone's short lived feature development), the problem of private or deleted forks shouldn't be an issue here.