I didn't really understand this concept until I saw a webpage on my local site that had PW standard 404 at the bottom, as if it was an iframe.

I'm working directly on the code of the live site, and getting to grips with ProcessWire (PW).

I wanted to rebuild the website of my personal, artistic work. The notion of just using HTML was very appealing, but I also wanted it to look like I'd made some effort. And I'd need some CSS to lay out the images anyway.