The report, widely criticised by both France and Ireland, the third bidding country, was not binding on the remaining members of the World Rugby Council, who voted in London.
Ireland had also entered a bid to stage the tournament.
The South African Broadcasting Corporation (SABC) will broadcast the World Rugby Council's announcement of the host country for the 2023 World Cup Rugby.
The second round saw France claim 24 votes to South Africa's 15 to be named hosts for a second time, after 2007.
The World Rugby chairman, Bill Beaumont, who announced France as the winners, said: "We were fortunate to have three great bids".
World Rugby publicly acknowledged receipt of that behind-the scenes letter on Friday, in order to consider the matter closed.
South Africa will be the visitors at the Aviva Stadium on Saturday Credit Getty Images
South Africa are still expected to land the honour having been deemed most suitable by last month's report. None of the three teams were allowed to change the details or their bid or offer inducements to council members but there were reports of the very horse-trading and lobbying that the process was created to prevent in the run-up to the vote.
The IRFU and the team behind our bid, however, have said that it is still possible for us to win.
World Rugby's technical review group had found South Africa's bid for the world cup to be the strongest.
World Rugby council members will have 39 votes in the secret ballot.
South Africa was previously stripped of the 2022 Commonwealth Games in Durban after failing to meet commitments, but Browne questions why the reasons behind this decision were not fully addressed in the report.
5.4 magnitude quake hits South Korea, tremors felt 300-km from epicentre
The quake was centered off the coast about 9.3 kilometers (5.8 miles) northwest of the port city of Pohang, according to the U.S. A number of windows were broken and walls crumbled beneath structures close to the central point of the quake .