The actual duplication is done in the Node.js runtime, not the V8 runtime inside of the Chromium GUI layer. I do wish they had a command-line version that just

The actual duplication is done in the Node.js runtime, not the V8 runtime inside of the Chromium GUI layer. I do wish they had a command-line version that just ran node without Chromium, but there is a use-case to have a simple foolproof application like this; these days there are a lot of people who need to image drives like this and would be best not to mess with dd on their first time. And dd doesn't exist for Windows so you've got to use some tool or another like this.