https://developer.mozilla.org/en-US/docs/Web/API/Event

The Event interface represents an event which takes place in the DOM.

An event can be triggered by the user action e.g. clicking the mouse button or tapping keyboard, or generated by APIs to represent the progress of an asynchronous task. It can also be triggered programmatically, such as by calling the HTMLElement.click() method of an element, or by defining the event, then sending it to a specified target using EventTarget.dispatchEvent().

The target property of the Event interface is a reference to the object onto which the event was dispatched

Value comes from the HTMLInputElement interface https://developer.mozilla.org/en-US/docs/Web/API/HTMLInputElement 605