Get it from OpenUserJS or Greasy Fork.
All the code does is lookup the videos source url, and add a link next to the video title.
There's a 5 second (5000 ms) delay at startup, the script won't work until the video is loaded. You may need to change this value depending on the speed of your internet connection.
For PCs simply Right Click or Command Click the Download Video link, and choose "Save link as..." option. On compatible mobile device browsers, you just have to Long Press, and choose "Save video". This also allows you to stream it to your Chromecast.
$( document ).ready(function() {
setTimeout(download_video, 5000);
});
function download_video(){
var video_url = $('#gator-video--1_html5_api').attr('src');
var download = document.createElement('a');
download.setAttribute( 'id', 'get_vid_link' );
download.setAttribute( 'style', 'color: #0097ee;' );
download.href = video_url;
download.target = '_blank';
download.innerHTML = 'Download Video';
$( '.font-mscon500' ).eq(0).append( ' ', download );
}