If you visit https://www.youtube.com/@Oxfordonlineenglish1/videos, there will be a video Talking About Online Shopping from the IELTS Exam Lessons playlist. And of course, you can click on the playlist label above its title and then you can watch all the videos from that playlist.
But if you visit the link above and then simply click "Playlists", the IELTS Exam Lessons playlist won't be listed there.
Does it mean you can have hidden playlists?