This simple docker image can be used to convert a .mbox file (for example from a google gmail account export / take out) to convert it to markdown files.
I used it for archive purposes, wanted to store my old gmail emails.
Nothing fancy, but usefull for those who dont want to use online converters nor mess with python directly.
NOTE: In my case, a 9GB .mbox file of a Gmail mail account took around 4-5 hours because the preperation of the html files takes in this in-efficient way some time. But it gets there eventually ;)