Instead of sending an AJAX request, the browser redirect the user to the result of the API request
The feature is completely broken. It was reported under https://commons.wikimedia.org/wiki/Commons:Village_pump#Anyone_else_having_problems_with_Flickr_uploads_.3F
Version: unspecified
Severity: major
URL: https://commons.wikimedia.org/wiki/Commons:Village_pump#Anyone_else_having_problems_with_Flickr_uploads_.3F