I'm not sure if this is an experiment, is the first time I see this popup. Here's how you can enable it:
- Go to YouTube and load your browser's developer console:
- Google Chrome: Tools, Developer Tools
- Mozilla Firefox: Web Developer, Web Console
- Internet Explorer: Developer Tools (F12), Console
- Copy and paste the following code:
document.cookie="VISITOR_INFO1_LIVE=j1l-QY6DlXg; path=/; domain=.youtube.com";window.location.reload();
- Press Enter and you'll see the experiment.
If doesn't work, try this other method:
- Open Chrome and install this extension.
- Go to YouTube and select "Edit Cookies" option on the context menu:
- Find a cookie named VISITOR_INFO1_LIVE and replace the value with this cookie value:
- Click "Submit cookie changes" and refresh the page.