Issue Summary

The landmark region is defined inappropriately for the content present in the "Diff" tab.

Steps to Reproduce

1. Navigate to "Pull request" link from the side navigation.
2. Now select any request from the table.
3. Observe that "View pull request" page has been opened.
4. Ensure that landmark region defined inappropriately.

Screenshot

Actual Results  

Landmark <header> defined to the content such as "readme.text", "Modified", "Mark as read", "Add a comment on this file", "View the entire source for this file", and "Diff view settings" inappropriately. As a result, screen reader users will find it difficult to identify the page structure.

Expected Results

Remove <header> element from the above mentioned elements.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available

Environment

MacBook Pro (16-inch, 2019)
macOS Ventura Version 13.6.1
Chrome - Version 120.0.6099.234 (Official Build) (x86_64)
Firefox- Version 112.0.1 (64-bit)
Safari- Version 17.3 (18617.2.4.11.9, 18617)
JAWS- Version 2022
NVDA- Version 2020.3