The Obama administration sent a declassified version of the document, with some redactions, to the congressional leadership on Friday. Its release on the website of the House Intelligence Committee later in the day marked the end of a years-long fight by lawmakers and families of the Sept. 11 victims to make public any evidence that Saudi Arabia may have played a role in the attacks.

It is by no means a Rosetta Stone that deciphers the lingering mysteries behind the attacks. But it is also a far more substantial document than many American and Saudi officials — from the White House press secretary to some members of Congress to the Saudi foreign minister — tried to indicate in a flurry of news conferences and emailed news releases on Friday afternoon.

And it was made public at a particularly troubled moment in America’s decades-long relationship with Saudi Arabia. The Senate unanimously passed a bill in May that would make it easier for families of Sept. 11 victims to sue the Saudi government for any role in the attacks. The bill is now being considered in the House.

The White House has threatened to veto the legislation, but the Obama administration has had its own recent period of tension with Saudi leaders over the Iran nuclear deal and the grinding war in Syria.

Much of the push over more than a decade to get the document declassified was led by former Senator Bob Graham, the Florida Democrat who was one of the co-chairmen of the congressional inquiry. In a statement on Friday, Senator Graham compared the release to the “removal of the cork at the end of the bottle” that should lead to even more information to be declassified.