The files in this repository host the ZipCPU blog articles via GitHub pages.
While you are welcome to browse these files via Github's interface, I personally think you'll find them much more interesting to look at from either the web-site's main page, the topics page which offers a categorical list of past posts and future posts, or the about page which will tell you more about Gisselquist Technology, the ZipCPU, and other projects/products that Gisselquist Technology provides.