Problem/Motivation
(/admin/content/files allows only to browse the files.
There seems to be no way in Drupal to overwrite a file, and keeping the same filename.
Deleting the file and replacing it with a new version while retaining the same filename does not work, as the new version would automatically get a prefix ("_0") attached to it each time a new version is uploaded (for example: "filename_0.pdf"; "filename_1.pdf", etc.).
"/admin/content/file/fiiename.pdf" seems to allow the file to be replaced when it is saved, but it still does not automatically replace it with the new version.
Proposed resolution
It should be possible to overwrite a file and keeping the same filename.
Original report by [dupal.user]
(There seems to be no way in Drupal 8 to to manually delete a file, other than waiting for some automatic cleanup of orphaned files.
Primitive solution: /admin/content/files may allow deleting files just as /admin/content allows deleting content.
Better solution: It should be possible to choose between deleting or unlinking previously uploaded file field attachments when editing a node.
Deleting is required in order to replace a file with a new version.)