Catherine Herridge of Fox News was able to elicit some comment on the testimony from Reps. Meadows and Jordan, though it remains confidential for now:

While the nation's media are consumed with Brett Kavanaugh's confirmation, intrepid heroes Reps. Mark Meadows and Jim Jordan, leaders of the House Judiciary and Oversight and Government Reform committees, were grilling the former top lawyer of the FBI, James Baker, behind closed doors. Baker, recall, was the right-hand man of James Comey and was closely involved in the FISA warrants that authorized electronic surveillance of the Trump campaign and presidency. Baker has since left the FBI. Some speculate that he is cooperating, but he notably came to the hearing with a bevy of lawyers representing him and the FBI.

"During the time that the FBI was putting – that DOJ and FBI were putting together the FISA (surveillance warrant) during the time prior to the election – there was another source giving information directly to the FBI, which we found the source to be pretty explosive," said Rep. Jim Jordan, R-Ohio. Meadows and Jordan would not elaborate on the source, or answer questions about whether the source was a reporter. They did stress that the source who provided information to the FBI's Russia case was not previously known to congressional investigators. Baker is at the heart of surveillance abuse allegations, and his deposition lays the groundwork for next week's planned closed-door interview with Deputy Attorney General Rod Rosenstein. Baker, as the FBI's top lawyer, helped secure the Foreign Intelligence Surveillance Act (FISA) warrant on Page, as well as three subsequent renewals. Prior to the deposition, Republican investigators said they believed Baker could explain why information about the British ex-spy behind a salacious Trump-related dossier, Christopher Steele, and Steele's apparent bias against then-candidate Trump, were withheld from the FISA court, and whether other exculpatory information was known to Rosenstein when he signed the final FISA renewal for Page in June 2017. Fox News asked Baker after the deposition about the handling of the Trump dossier, what he told Rosenstein about exculpatory evidence, and whether he is the subject of an FBI leak investigation. Baker told Fox News he could not answer such questions.

John Solomon of The Hill, another ace reporter with good sources, has identified what may be the "explosive" source:

Congressional investigators have confirmed that a top FBI official met with Democratic Party lawyers to talk about allegations of Donald Trump-Russia collusion weeks before the 2016 election, and before the bureau secured a search warrant targeting Trump's campaign. Former FBI general counsel James Baker met during the 2016 season with at least one attorney from Perkins Coie, the Democratic National Committee's private law firm. That's the firm used by the DNC and Hillary Clinton's campaign to secretly pay research firm Fusion GPS and Christopher Steele, a former British intelligence operative, to compile a dossier of uncorroborated raw intelligence alleging Trump and Moscow were colluding to hijack the presidential election. The dossier, though mostly unverified, was then used by the FBI as the main evidence seeking a Foreign Intelligence Surveillance Act (FISA) warrant targeting the Trump campaign in the final days of the campaign. The revelation was confirmed both in contemporaneous evidence and testimony secured by a joint investigation by Republicans on the House Judiciary and Government Oversight committees, my source tells me. It means the FBI had good reason to suspect the dossier was connected to the DNC's main law firm and was the product of a Democratic opposition-research effort to defeat Trump – yet failed to disclose that information to the FISA court in October 2016, when the bureau applied for a FISA warrant to surveil Trump campaign adviser Carter Page.

Sundance of Conservative Treehouse comments:

The fact that FBI officials were meeting with a lawyer representing the interests of a presidential candidate to frame investigative material against the candidate's opposition is a serious issue. Then again, with overwhelming evidence highlighting the plot – by now everyone accepts this corrupt activity took place within the FBI under James Comey to the secret benefit of the Hillary Clinton campaign. Of course the use of Perkins Coie lawyers as a go-between provides Clinton plausible deniability. Every corrupt behavior in Clinton world is based on plausible deniability and parseltongue use of obfuscated language. Additionally Joint Committee republican representative Mark Meadows told The Hill's new morning television show, Rising, there is evidence the FBI had human sources secretly recording members of the Trump campaign: "There's a strong suggestion that confidential human sources actually taped members within the Trump campaign," Meadows told Hill.TV hosts Krystal Ball and Ned Ryun. (link) If true, and if it can be proved, this puts an even bigger shadow over the insufferably corrupt institutional behavior already identified within the DOJ and FBI under the Obama administration.

Meanwhile, declassification of the FISA warrant applications is apparently being slow-walked. With a bit more than a month, there is still time before the midterms to reveal to the public the depth of the corruption.