2021-11-16: Prior to commit `7858dba48b41417f951031d36e7fbf66da8d14e2'
            DFS visualization is not perfect. Solutions generated
            after the mentioned commit should be correct. Everything
            before DFS-51 was generated prior to this commit.

DFS-51: 4875913 lines, 732M, 14M (compressed `xz -9')

        This file is not added to the repo.