What does "<style>" refer to in Chrome developer tools "Styles" tab?

Question

I can't find any references to this anywhere, in fact Google seems to be willfully ignoring my use of quotes to force its inclusion -- "<style>". In the area where it would usually indicate which CSS file was providing the style on an element, instead it shows <style>:

This is on an element that clearly has no styles defined on itself:

So what does that mean? What is it referring to?

Answer 1

To make the comment an answer:

It means there's a <style> element on the page with those rules, e.g.

<style>
.edit-action-dialog ... { ... }
</style>

You can use e.g. document.querySelectorAll("style") to enumerate those.