From the article, should be of interest to those wondering about the legal requirements rather than the emotional ones.
"Under the regulations that governed his appointment and now guide his final acts, Mueller is to provide a confidential report to one person only: the attorney general. The regulations, which were promulgated 20 years ago during the final months of the Clinton administration, do not contemplate any sort of report sent directly from the special counsel to Congress or the general public. To the contrary, the regulations call upon the attorney general, William Barr, to receive the confidential report and then do two things: First, to notify Congress of the investigation’s completion and, second, to provide an explanation for certain specifically enumerated actions. There is no requirement for a Barr-edited version of the Mueller report."