I have Research about it and they will display for each login form of frontend and backend login form, Its normal flow and each time they display correct username and password of current users data. They don't rely on any mode of magento.
You can check it from file for both backend and frontend, By default, they will pass data with input field and you can check code from below file.
For Backend file,
vendor/magento/module-backend/view/adminhtml/templates/admin/login.phtml
For Frontend file,
vendor/magento/module-customer/view/frontend/templates/form/login.phtml
So each time after login from any area they will display username and password of the current registered user.
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