The whole section on "What's the difference between Web Server and Application Server?" is not very precise. I wouldn't say the difference has to do with content type being served. I think it would be better to talk about responsibility in the stack. A quick google search yields this page from IBM ( https://www.ibm.com/cloud/learn/web-server-vs-application-se...) which IMO provides a clearer explanation. There is also something called reverse proxy which I think is important but is missing.
Another diagram has the app + web server within the same physical server. While it gets the point across I think it would be better to use an example where this is not the case. From my experience it is usually not the case.
