It was written in 2019. He even mentions that at a few points.
> Today in 2019...
> Now, in the year 2019...
> Up to now (2019)...
> Today in 2019...
> Now, in the year 2019...
> Up to now (2019)...
But given the uselessness of his git commit messages, I'm not inclined to judge leniently.
https://github.com/guettli/deadends-of-it/blame/master/READM...