How to upload another format through the admin(upload) panel?

Question

opencart

Need to allow the standard file uploader located in the admin panel (directory - downloads) to upload other formats: mp3, mp4 and others? Reshared the download.twig controller, download.php and download_form.twig. But, I did not find anything reminiscent of what could change the download format.
Where to find these formats, where to allow them?

Answer 1

1) Find a section of code where filtering by file types takes place. Add avi, mp4, etc. there
2) Find the section of code responsible for the output, set the condition there - If the video file, then everything is for playback.

Answer 2

Admin/System/Settings/=store name= , "Server" tab
Allowed file types and mime types