This tweet, which has been shared 8,500 times + (and counting) is basically disinformation. The data is freely available online & has been for months. You can search it yourself here. What actually happened on the Russia 'dark web' forum is rather funny.
https://michiganvoters.info  https://twitter.com/juliaioffe/status/1300771489847955456

You see, the US offered a $10 million reward for anyone who could prove foreign states were interfering in the American election. So, the Russian 'hackers' were discussing how to play Washington for laughs & claim the reward cash.

One user said he got $4,000 from the US government for sharing a link (take with a large pinch of salt). Another pointed out source, a regularly updated website, supposedly used for genealogical research, that cites FOIA requests for the data. Here's a page of Brian McDonald's