Earlier this evening, the news broke that Special Counsel Robert Mueller had concluded his investigation and presented his findings to Attorney General William Barr.  At long last, the probe -- Mueller's portion of which dated back to May 2017 -- is over.  Here are some key observations about what we know, and don't know, at this hour:

(1) We do not know virtually anything about the content of Mueller's report, which is the most important information in all of this.  According to AG Barr's letter to the Chairmen and Ranking Members of Congress' Judiciary Committees, some top-line findings could be disclosed as soon as this weekend.