Link to Fluendo site in "Why won't DVDs play" is incorrect
The bug has been reported on https://launchpad.net/bugs/1805708 and that's still an issue with git master
https://gitlab.gnome.org/GNOME/gnome-user-docs/blob/master/gnome-help/C/video-dvd.page#L49
hints to go to http://fluendo.com/shop/product/oneplay-dvd-player/
but that URL is not valid
'https://fluendo.com/en/products/multimedia/oneplay-dvd-player/' does work though so maybe that one should be used instead?