This is harmless for the download_by_url action when used with a tar-ball or other archive as we unzip that and change into the child directory. However, this would cause problems for the download_file action.

See https://github.com/galaxyproject/planemo/blob/master/planemo/shed2tap/base.py

There is partial code in place to use the target_filename but nothing actually captures this from the HTML tag, so clearly I never finished this.