Привет! As haiku-os.pl does not exist, I should fill the gap.
https://premislaus.github.io/categories/Open-Source/Haiku/ - That webpage is fully developed under Haiku. Node.js, Hexo, Koder, Terminal and especially Stack & Tile, are very powerful and modern set of development tools.
The site is not only about Haiku because computer use is part of a larger whole.
You can read in English thanks to Google Translate with 90% language precision.