@Kami. Thanks for your question. This issue with Safari and the addition of the “.html” is not exclusive to the plugin. However, you may be able to try somethings to see if it makes a difference. When I test the plugin using Safari on my MAMP server, I do not get this issue. So, since I am unable to replicate your problem, I can only make some suggestions on possible ways to fix it.
From what I understand it could be the Content-Type setting. So what you can do is open “download.php” and change “header(“Content-Type: application/octet-stream”);” to either:
Let me know how it turns out.