It’s been nearly a year since the US intelligence community publicly announced its determination that the Russian government took covert actions to sway the 2016 US election. We now know that Russia did so in part by buying Facebook ads and weaponizing bots, trolls, and other social media tools created by US tech giants. But there is still much that eludes the public about these attacks, as New York Times media columnist Jim Rutenberg pointed out on Monday: We don’t know what these Facebook ads looked like, we don’t know who they were targeting, and we don’t know how many millions of Americans may have been exposed to them. As the Washington Post reported, congressional investigators “have grown increasingly concerned that Facebook is withholding key information that could illuminate the shape and extent of a Russian propaganda campaign.”