In a nutshell, it seems that everything went wrong, and the entire incident was the almost unavoidable outcome of policy failures, bureaucratic mismanagement and miscommunication, dismal understanding of the situation in Libya, gross underestimation of necessary security to protect Americans, and general fumbduckery. Meaning that no one - especially Hillary in the Left's estimation - is to blame because the entire system failed at every level.
For Progressives, this means that Hillary is now cleared and qualified to become president of the United States, an office from which she can give every citizen the same level of protection she provided for the fallen in Benghazi.
Interestingly, the report makes clear that pretty much everyone in the Obama administration, including Hillary, lied their pants (or pantsuits) off about what actually happened - choosing to promote their entirely bogus "Youtube demonstration" story in order to not distract Americans in an election year with the troublesome truth that the war on terror hadn't really ended with Bin Laden's death. Hillary Clinton knowingly lied to the victims' families when she told them that the videomaker would be brought to justice, and subsequently lied when she accused those still-grieving family members of being liars themselves for failing to cover her polyestered rear end.
Democrats on the investigative panel issued their own version of the report, declaring that the whole Republican-led investigation was a political sham intended only to sully a presidential candidate's reputation, which is an unacceptably sleazy and partisan thing to do. The Democrat report then somehow inserts 23 negative references to Donald Trump, which is apparently an acceptably sleazy and partisan way to sully a candidate's reputation.
While it would seem that the fat lady has sung, or in this case cackled, on the sad subject of Benghazi, Hillary was in no way exonerated. The full report notes that the record of Hillary's actions or inactions will never be complete owing to her use of the infamous, secret private server and deletion of tens of thousands of emails.
Which, unlike the fatal miscalculations made about embassy security, shows impressive foresight on her part.
FLASHBACK: PROPHET AND LOSS STATEMENT (9/26/2012) - Obama uses Benghazi deaths to defend Islam and attack the 1st Amendment at the United Nations.