Through some trial and error and some [further][1] [digging][2], I figured it out. Here's what works:

URL: `[entityform:field-file-upload:0:file:url]`

Filename: `[entityform:field-file-upload:0:file:name]`

Upload date: `[entityform:field-file-upload:0:file:owner:created:short]`

Increment the `0` to return more files from the multi-value array of uploaded files.


  [1]: https://drupal.stackexchange.com/questions/50068/rule-to-send-an-e-mail-with-the-url-of-an-uploaded-attachment-after-node-change?rq=1
  [2]: https://www.drupal.org/node/390482#token-file