This page is designed to test the file upload feature and it's related optional modules.
These optional modules include 'modreqparser', which can be used to optimize file upload to pass the path of uploaded files instead of their contents, and 'uploadprogress', which can be used to display a progress bar for the current file upload.
If context "/progress" is set to be handled by the "uploadprogress" module, then the progress request for this file will work as intended, displaying a working progress bar.