Taken from this suggestion, go to https://takeout.google.com/ and click the "Deselect all" hyperlink, scrolling to the end of the page to check "YouTube and YouTube Music."



With the "Multiple formats" button below, premium users may get an alternative to csv in their output. just to the right of it there is an "All youtube data included" button. Click it, (see graphic) again click "Deselect all" at the top, select playlists below, and click the ok button. Optionally check music-library-songs, as that file contains the full url and the video description, which the playlist does not have. Click "Next Step" below, and, then if the defaults seem reasonable, click "Export".

The export duration should be short, after which a username/password prompt provided for file access. Navigate to the Downloads location for the takeout-yyyymmddid_number-001.zip and navigate the archives in the zipped file \Takeout\YouTube and YouTube Music\playlists to Liked videos.csv and the optional music-library-songs.csv in the other zipped directory.

The music-library-songs appears to be a more recent addition in the personal collection, thus the liked videos only go back 2-3 years or so. This is an instantly searchable list, whereas the older video ids in the playlist must be ported to a search script where they will be url encoded.

Taken from this suggestion, go to https://takeout.google.com/ and click the "Deselect all" hyperlink, scrolling to the end of the page to check "YouTube and YouTube Music."



With the "Multiple formats" button below, premium users may get an alternative to csv in their output. just to the right of it there is an "All youtube data included" button. Click it, (see graphic) again click "Deselect all" at the top, select playlists below, and click the ok button. Optionally check music-library-songs, as that file contains the full url and the video description, which the playlist does not have. Click "Next Step" below, and, then if the defaults seem reasonable, click "Export".

The export duration should be short, after which a username/password prompt is provided for file access. Navigate to the Downloads location for the takeout-yyyymmddid_number-001.zip and navigate the the folders in the zipped archive \Takeout\YouTube and YouTube Music\playlists to Liked videos.csv, and also, optionally, to the music-library-songs.csv in the adjacent directory.

The music-library-songs appears to be a more recent addition in the personal collection, thus the liked videos only go back 2-3 years or so. This is an instantly searchable list, whereas older video ids in the playlist must be ported to a search script where they will be url encoded for web verification.