Source: https://moviemaker.minitool.com/moviemaker/download-jw-player-videos.html
Inspect Element
The easiest way to download JW player videos is using Inspect Element. Below are the detailed steps on how to download JW player videos.
Step 1. Open the website where the JW player video is located.
Step 2. Right-click on this webpage and choose the Inspect Element (or Inspect) option.
Step 3. Then go to Network> Media.
Step 4. Press the F5 key to refresh the webpage and play the video.
Step 5. Later, you will see an MP4 file shows in the box. Right-click on it and open it in a new tab. After that, this JW player video will be downloaded automatically.