Spencer Walden's information security blog's source code. It primarily works by using the contents in the _posts directory and rendering them nicely. It is a static site, so it's pretty lightweight as well on browsers.
Jekyll and Chirpy. They have some licenses that I'd like to try my best to respect, and so have listed some of them below. Thanks to the developers/authors of those projects, they make this blog/project possible and easy.
Chirpy (and the projects it uses) are published under the MIT License.