The 300 or 700 or whatever pages are the summary. WH and campaign alone turned over a million pages.
The article, which aims to convince the reader "Trump is sunk" is somewhere in the report, has a list of the length of past Independent Prosecutor and Special Counsel reports. 700 pages is longer than Watergate, Starr, Waco, and all the others. 300 pages is about average for such whitewashes the government puts out to mollify the public in (so far successful) efforts to prevent the public from becoming restive.