What do we not know about 9/11?

Is there anything left in the thousands of pages of classified FBI and CIA documents about the 9/11 investigation which could totally change everyone's view about what happened in the lead-up to the terrorist attacks and in the immediate aftermath? Somehow I doubt it. Joe Biden has authorised the release of previously secret documents as he promised he would during his presidential election campaign. The documents will be released over a period of six months and will keep curious reporters and historians, and most importantly the families of the near-3,000 victims of 9/11, fully occupied. As with the murder of Saudi dissident journalist Jamal Khashoggi in 2018, the Saudi government has always denied any involvement in financing or supporting the al-Qaeda hijackers, 15 out of 19 of whom were Saudi nationals. No evidence was ever found by the congressional commission into 9/11 published in 2004. And you do have to wonder why on earth the Saudi government would want to support such a devastating terrorist attack on a country it deems to be a friend and ally, and business partner. There WAS financial support coming out of Saudi Arabia but not from the government. Nevertheless the families of the victims want to read the FBI evidence to see if there is even a hint of an official Saudi connection during what was the biggest investigation ever undertaken by the law enforcement agency. Like the assassination of John F Kennedy, I suspect that we will never learn the whole story. The new declassified FBI documents will be fascinating but I don't think anyone who reads every word is going to be able to say: "So now we know what really happened."