It was visible externally because the OpenAI agents wrote a script that modified that file so that when an HF worker went to load that data set it would also direct the worker to load an additional malicious file. The script added the malicious redirect, but kept everything else in README as is which meant the script had to contain the entire existing content from the README so that it could write that back to the repo.

The warning likely wasn’t the only security measure on the repo and I don’t think the warning is intended to actually stop malicious behavior. It reads like a reminder to prevent careless behavior. You can give people all the security training in the world and still have the situation where someone who rightfully has access to that dataset decides to absentmindedly drop it in a public Slack channel. Having something like that increases the chances that someone then goes “Hey Bob, did you mean to share that publicly?”