When you search a file in your repository and clicks it.
The page will redirect you to the specific file which you've just clicked.
In that page, there's a "Pull Requests" button.
When clicking it, the pop-up result provides PR that isn't related to the file.
The result is a bit confusing and somehow irrelevant in the searched file.
It would be best if we can provide more information (like labels) as to what the "Pull requests" button does and how it realated to the file.