Firstly, I'm going to start with a link. This link contains multiple other links to articles about the JFK Assassination, the documents that were released/withheld, what the government could be hiding, ect. Apparently the government, according to the National Archives, released only 88% of the documentation surrounding the assassination of JFK, 11% was censored in some way or was released in parts. 1% wasn't released at all. According to the 2017jfk.org website, the documentation consists of 3,810 documents in total, 441 of which were censored, all originating from the FBI or CIA. (The website also lists ways to view the released documents)
The supposed 441 documents are to be released on October 26, 2017 according to the "John F. Kennedy Assassination Records Collection Act of 1992" signed by George Bush Sr.
Why is this "important?" Well, according to Bryan Bender over on POLITICO (Fantastic article that explains way more and goes far further in depth),
"Based on what has been revealed previously, many of the files are expected to have no direct bearing on Kennedy’s death in Dealey Plaza but could reveal intelligence operations involving Cuba, secret relationships between U.S. spy agencies and unsavory characters during the height of the Cold War, as well as other secrets the U.S. government might have resisted disclosing publicly as part of a full and open investigation at the time."
So again, why is this important? It probably isn't as important as we think. The government wouldn't release incriminating documents. And it's not like if in the event anything Earth shattering being released, that we can do anything about it. It was 54 years ago. However, it will be interesting. Testimonies of people who allegedly had ties with mafia members in Cuba who were hired to overthrow Castro, Testimonies from Watergate burglars, CIA "personality" studies on Oswald, and communications of the FBI director at the time. Could be interesting.
Here's one other video by the National Archives about the subject: