UPDATE: unbelievable but this is already not up to date only a few months later...

Here's an answer for 2020:

> [youtube.com/my_liked_videos][1].



It seems like some of the stuff here is outdated but I must say @jopisa's answer is great it's most likely a feature which has been removed from the YouTube GUI but not deactivated so you can still reach it by using the right URL. Using the URL provided in @jopisa's answer will filter the videos you liked but no longer have access to them (they were removed from YouTube or became private) and shows them _not_ in a playlist.


  [1]: https://www.youtube.com/my_liked_videos