Usability Review: Programming Historian

As a non CS major-- and, to be frank, a person with a fairly basic grasp on technology as a whole-- one thing I'm interested in is applying this lack of knowledge to assess the reality of accessibility on websites, specifically those intended to teach basic programming skills. I first looked into Programming Historian as an alternative to the somewhat DIY programming and instruction, often found in the depths of non-didactic/non-programming websites like Reddit or even Twitter. The goal was to, hopefully, learn a little something, but more importantly, as a someone who grasps just the most essential basics of computer science, to comment on the accessibility of these pages.
I chose the Programming Historian post regarding the creation of Twitterbots, a topic that required a little reading up on, as it was a function about which I knew the basics of the so-called "front-side," but not the "back-side," or the programming end. However, Programming Historian itself did a lot of the work for me with thorough introductions to both the outward function of the bots, as well as the software behind them. The site itself walked me straight through working with Tracery, an editor that at first glance appeared more confusing than it actually was. Once the "bot" was created on Tracery, that software could be translated into JSON, then plugged into a website that uses the data to create an actual bot. As a non-CS major who has used this tutorial and come out the other side understanding the creation behind Twitterbots fairly well, I would say that this page is absolutely usable, even for someone like myself who can barely figure out twitter; if you're looking for some concrete evidence, I made a TwitterBot, GouldLibeBot, @GouldLibraryBot, a Bot that tweets out different variations of things that happen in the library in less than 10 minutes from this tutorial. In terms of accessibility, however, thinking outside of myself, I'm not sure the page would be usable without plugins for a person with some sort of disability, specifically blindness-- I saw no viable pathways to listen to the page. However, the site is completely free, and thus is totally accessible to perhaps a low-income student. Overall, I was impressed that I could glean anything about coding in less than twenty minutes from my own computer without compromising my own non-digital background!