Conceptually yes, but specifically it's implemented by intercepting the browser's internal fetch process. So it's like a "browser-internal" proxy -- or not a proxy at all.
You could do something similar with a proxy, but it may run into issues with HTTPS, which this gets around as we are beyond the terminator. In this way, you can serve the content, and save the content, via getting in the middle of the same fetch process and the browser doesn't know the difference (mostly).
You could do something similar with a proxy, but it may run into issues with HTTPS, which this gets around as we are beyond the terminator. In this way, you can serve the content, and save the content, via getting in the middle of the same fetch process and the browser doesn't know the difference (mostly).