How to reproduce: In a legacy Tuleap version (prior to December 2025) you can go on docman, copy an image and paste it in an artifact in ckeditor in html mode. The image will be displayed and it will have an URL like (https://tuleap/plugins/docman/?group_id=103&action=show&id=5 in the html part of editor). Switch back to the current instance of Tuleap: the image won't be displayed

Why? In 753b6c3220ff9ec087ecc877a2e0da2c623cfc3a the redirection is not properly done. Accessing to an old url will display the current preview of the item and will display a warning message. We should redirect to the download url for files and make the redirection transparent.