Developing for the browser is a real challenge. I think working with html / css /js has been a neglected skill for a long time - most software engineers look down on that type of work and its rarely covered in comp sci course work.
Still, its good to see a lot of progress has been made, this book included.
My only critique - why use python instead of node.js?
Basically: server-side JavaScript is just not as widely known as Python, and it'd be additionally confusing when our browser starts running JavaScript. And in-browser JavaScript is a bit too restricted (by things like the same-origin policy) to do the whole thing inside a browser.
I am resisting the urge to disagree, but since you did (literally) write a book about building a browser, I will defer to your expertise and try to learn from you :)
Respect
Does it have RSS?
I don't think either is a super compelling choice anyways for this type of work. I think you want to use a systems language here. However Python is completely fine as a teaching language. Pretty much anyone who knows a similarly structured language can read it. And there is very little noise. So it can serve as a good reference if you want to follow along with a different language.
IMHO, those are job skills and not comp sci topics. They shouldn't be part of a degree program (except the most superficial treatment required to get some ugly UI up that may be required for something else). You have your whole career to pick them up.