Component Events and Event Data (v14)

I am trying to find the correct way to determine the available events and event data for a component. I have seen in the documentation “Using Events with Components” that is refers you to “See Event in the MDN web docs for an overview of standard DOM events and properties.” So that is helpful although I still found it fairly difficult to determine the exact element and event data items that are available.

Also, I happened to come across [this]
( example of a listener on the splitlayout event and accessing the element.primaryChild.offsetHeight event data. I cannot see where this is covered in the documentation?

Is there a right process to follow or documentation to reference to discover all the correct events and event data items available for a particular component?