how do we activate the debugger?

To enable debug mode, set the debug configuration option to true when initializing the Mixpanel object. You can then check the debug info in the Browser console directly. -- https://developer.mixpanel.com/docs/javascript#debug-mode E.g

There are other third-party tools to debug like this Chrome extension: https://chrome.google.com/webstore/detail/mixpanel-tools/eifepbfdgonblafppielmnnihcopdlpo. Hope this helps!