Why does Drupal store the uploaded files for a content node even if the content is not created?
I have discovered that the files are physically stored, and also in the database, there is an entry in the table file_managed with the field status with the following indication and value : 0

A field indicating the status of the file. Two status are defined in core:
temporary (0) and permanent (1).
Temporary files older than DRUPAL_MAXIMUM_TEMP_FILE_AGE will be removed during a cron run.


I have manually changed the timestamp of the uplodaded file, run the cron, and the file dissapears. Obviously there must be a confident time, because if not, files in contents still being update could have the risk of being deleted. My fault for not thinking of this last point.