FFmpeg Library Download button broken

I tried to open a file encoded with FFmpeg however didn’t have the library installed.

Going to Preferences → Libraries there is a ‘download’ button shown in the attached screenshot.

However the resultant webpage when you click it is 404 so this link will need to be fixed, either within the app itself or by way of redirect on the webserver from its former, now missing, location.

Which version of Audacity are you using? (Look in “Audacity menu > About Audacity”)
What web page does it go to?