Unread XKCD

Check out the source code on GitHub: https://github.com/jeffreymeng/unread-xkcd Note: this extension has limited ability to load your _past_ history, so it can only make sure that when you click the "Random Unread" button, you don't see any xkcd comics that you've seen since installing the extension (your browser history from the past 90 days can optionally be locally scanned through the extension settings, but data before that isn’t accessible due to chrome limitations)