Senator Dianne Feinstein (D-CA) has requested a significant amount of data from Twitter and Facebook ahead of their presence at a Senate hearing about Russia's interference in the 2016 election. Feinstein is asking for data about the accounts set up by Russia for the sake of disinformation.
Though Facebook did provide 3,000+ ads to the US government, it didn't give the Senate access to the content posted by Russia-linked accounts. That's the sort of information Feinstein wants.
Both companies have been asked to provide posts, IP addresses, and identifying information.
Some of the requests specific to Twitter cover all of the direct messages to/from WikiLeaks founder Julian Assange and additional info on Guccifer, the hacker accused of breaking into the DNS's email servers.