Here's a screenshot of an accessibility tool...
The header is not ideal in some modes.

What can be fixed?
Context-
Pre - Requisites:
Turn on Windows Settings
Search "Contrast themes" under accessibility section.
Tab to Contrast theme dropdown and "Select desert" from the list.
Tab to Apply Button and press enter.
Refresh the page.
Repro Steps:
Hit the application url :Microsoft Open Source and login with appropriate credentials.
"Open Collaborative Flexible" page will open.
Tab to Microsoft and Open Source link.
Observe the issue
Actual Result:
In High Contrast – Desert theme, the text “Microsoft and Open Source” has a color contrast ratio of 1.041:1 against its background. This is significantly lower than the required minimum contrast ratio of 4.5:1 for normal text, making the text difficult to read.
Expected Result:
The “Microsoft and Open Source” text should maintain a minimum color contrast ratio of 4.5:1 against its background in the High Contrast Desert theme, ensuring the text is clearly visible and readable for all users.
User Impact:
Users with low vision, color vision deficiencies, or those relying on high contrast themes may not be able to read or identify the “Microsoft and Open Source” text due to insufficient contrast.
Here's a screenshot of an accessibility tool...

The header is not ideal in some modes.
What can be fixed?
Context-
Pre - Requisites:
Turn on Windows Settings
Search "Contrast themes" under accessibility section.
Tab to Contrast theme dropdown and "Select desert" from the list.
Tab to Apply Button and press enter.
Refresh the page.
Repro Steps:
Hit the application url :Microsoft Open Source and login with appropriate credentials.
"Open Collaborative Flexible" page will open.
Tab to Microsoft and Open Source link.
Observe the issue
Actual Result:
In High Contrast – Desert theme, the text “Microsoft and Open Source” has a color contrast ratio of 1.041:1 against its background. This is significantly lower than the required minimum contrast ratio of 4.5:1 for normal text, making the text difficult to read.
Expected Result:
The “Microsoft and Open Source” text should maintain a minimum color contrast ratio of 4.5:1 against its background in the High Contrast Desert theme, ensuring the text is clearly visible and readable for all users.
User Impact:
Users with low vision, color vision deficiencies, or those relying on high contrast themes may not be able to read or identify the “Microsoft and Open Source” text due to insufficient contrast.