Jekyll (Plain Text/ Markdown to Blog)

https://jekyllrb.com/

https://github.com/jekyll/jekyll

Jekyll is written in Ruby: https://jekyllrb.com/docs/ruby-101/

MIT License: https://github.com/jekyll/jekyll/blob/master/LICENSE

Tutorials: https://jekyllrb.com/tutorials/home/

Tags und Categories

https://blog.webjeda.com/jekyll-categories/

Themes

http://jekyllthemes.org/

https://jekyllthemes.io/

http://jekyllthemes.org/

https://jamstackthemes.dev/ssg/jekyll/

https://jekyllrb.com/docs/themes/

https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll/about-github-pages-and-jekyll

Liquid

https://shopify.github.io/liquid/

https://jekyllrb.com/docs/liquid/