Since I have been using the ActivityWatch Browser Extension, Google is warning me about malware on my PC. Is this because of the ActivityWatch Browser Extension? I had it installed on Edge, and my antivirus doesn’t show anything yet.
That would be extremely unlikely.
That’s my guess too and I’m pretty sure you are right. Regarding what happened afterwards, I ran malwarebytes and couldn’t find anything. In the meantime, when this was happening, my GitHub account I was logged into with the browser ended up making malicious edits to wiki pages without me knowing and my account was permanently banned. I uninstalled the extension and since then did not get any error from Google.
In any case, here is the link of the extension I was using: ActivityWatch Web Watcher - Chrome Web Store