Where does "entity" coming from when you look at variables in twig debug?

Hello,

In my theme, I wanted to output an img tag with the image’s src attribute. I found that the way to do that is (example):

file_url(content.field_example_image['#items'].entity.uri.value)

So I have installed Twig Xdebug (https://www.drupal.org/project/twig_xdebug) and looking at the debugger, neither the image (field_example_image) nor its array (field_example_image[‘#items’]) have a member called ‘entity’. So where does the ‘entity’ coming from?

I looked at the variables in kint output as well, but there’s nowhere in sight a variable called ‘entity’. So how can someone ‘figure out’ that there is a variable called ‘entity’ that needs to be used in order to figure out the src of an image?

Sure, I can copy paste this into my twig template and call it a day (after all it does work), but I’d like to understand where do you find this ‘entity’?

Thanks.

(using Drupal 8.6.x)

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