Why tabs belong to “search” section rather than to “content” section in Google?

What is the rationale behind keeping tabs visually connected with the search section rather with the results here? I've also seen this pattern in accordions.

I would understand if selected options would have same background as results, visually reinforcing connection between the two. But in this case it just an underline.

So it's interesting why would one want to keep tabs visually connected to search rather than to the content.