From Thomas Ptacek on twitter [1], quoting something on HackerNews [2]: a person wrote a dot-file renderer for ASCII diagrams [3] It seems to be a service; source not available.

1. https://twitter.com/tqbf/status/1483181795441004544?t=DoL8RopOYKBojkmMznSlAA&s=03

2. https://news.ycombinator.com/item?id=29969770

3. https://dot-to-ascii.ggerganov.com/