How is this not entirely illegal?
And it certainly shows an incredible flaw in Chrome extensions. This extension didn't do this when I installed it. A silent auto-update though basically turned it into the worst malware I've ever had installed on my computer. How can any Chrome extension ever be trusted?
Furthermore, I spend a lot of time in Chrome Dev Tools, and the Network tab and I are no stranger. I would easily have noticed if my keystrokes were being sent back to a server and it was shown in there. So not only can an extension be silently updated, but it's capable of using a network connection that doesn't appear in the Chrome Network tab, that only Wireshark can reveal? That seems almost as ridiculous as what the extension author did.