I am afraid that the author has disqualified himself by publishing the source code before the judging of IOCCC 2020 is over. See catch 22 in the rules: "The judges STRONGLY prefer to not know who is submitting entries to the IOCCC."[1] Even the winners are asked not to publish the code until it is available on the IOCCC web site.[2]
[1] https://ioccc.org/2020/rules.txt [2] Personal communication