Can you inspect a WebElement with Firebug if WebDriver opens the Browser?

Yes, even if WebDriver opens the browser, you may use Firebug to inspect a WebElement.

Inspecting a WebElement using WebDriver is similar to doing it with Firebug or another browser development tool. You may use the browser's inspect element capability by right-clicking on the WebElement you wish to inspect and choosing "Inspect" from the context menu.

You can use the element inspection tools included with WebDriver. For instance, in Python, you may extract an element's properties and values using the element object's get attribute() method of the element object, which can help debug and troubleshoot.