https://techcrunch.com/2019/04/17/mueller-report-cd/

If there weren’t enough obstacles already standing between Congress and the results of the special counsel’s multiyear investigation, lawmakers are expecting to need an optical drive to read the document.

A Justice Department official told the Associated Press that a CD containing the Mueller report would be delivered to Congress tomorrow between 11 and noon Eastern. At some point after the CDs are delivered, the report is expected to be made available to the public on the special counsel’s website.