Thats nothing compared to the amount of fake twitter accounts for paid followers. Probably in the range of 100s of millions of accounts. For the downvoters, or doubters, goto https://www.fiverr.com/ and see if you don't find these services being offered all over the damn place. 1 million followers for 20 bucks.
Yes, I think this is what he means, that this list could have been leaked from some "bot controller" server/network. Or maybe the bot network wants to quit and is selling their assets.
This would be coherent with Twitter denying a breach, these would be accounts hacked at some point of the past (and some purposefully generated) and added to the bot network database.
