Confused about who’s who in the Mueller report? Start here.

The Mueller report will be released Thursday, giving the public the first real glimpse of the details of the special counsel’s findings on Russian interference in the 2016 election and whether President Donald Trump tried to obstruct justice in the course of that investigation.

Special counsel Robert Mueller was appointed in May 2017, and in the nearly two years that he oversaw the investigation, his team issued more than 2,800 subpoenas, executed nearly 500 search warrants, and interviewed approximately 500 witnesses, according to what Attorney General William Barr told Congress...