Is there an event.source attribute-documentation?

I'm trying to get a child-element based on the event.source name, but can't for the life of my find any documentation on what attribute I can call to achieve this. As a matter of fact, I'm having a hard time finding any documentation regarding elements that specifies attributes and return-types.

Most likely this is my inability to formulate coherent google-searches, but I'm hoping someone can steer me in the right direction. When searching this forum, I notice there are plenty of attributes to event.source, but the autocompletion shows exactly zero of them.

There's no documentation because event.source is a chameleon. It carries an arbitrary object, which can be a window, a container, a grouping object, a shape group, or any component or template. You are expected to know, based on where you placed the event, what kind of object it is, and use that object's documentation.

If you don't know what the object is officially called, you can script this:

print type(event.source)

It will return what you need to search for to find the correct documentation.