Note that this page has no category theory yet since it explains sets, so if you already know sets, set product, etc and want to learn about category theory, my advice is to go directly to the next chapter, more specifically to this section:
The author said he is just starting on the book, so he's not claiming it's perfect. And the beauty of github, open source is you can fix them with a pull request. For example, the svg is here:
https://github.com/abuseofnotation/category-theory-illustrat...
Note that this page has no category theory yet since it explains sets, so if you already know sets, set product, etc and want to learn about category theory, my advice is to go directly to the next chapter, more specifically to this section:
https://abuseofnotation.github.io/category-theory-illustrate...
which uses set theory terms to define the category theory way of defining products (the corresponding "universal property").