Chrome, Firefox, Vivaldi and Safari support getEventListeners(domElement) in their Developer Tools console.
For majority of the debugging purposes, this could be used.
Below is a very good reference to use it:
https://developers.google.com/web/tools/chrome-devtools/console/utilities#geteventlisteners
Highly voted tip from Clifford Fajardo from the comments:
getEventListeners($0) will get the event listeners for the element you have focused on in the Chrome dev tools.