samples

plugin://plugin.video.youtube/play/?playlist_id=PLFgquLnL59akhdhcSukD-WMIBEFW53iYT

and you're done. If the playlist is public (which is common) no login is needed.

Additionally you can provide the order, so the addon won't ask.

default order:
Code:
plugin://plugin.video.youtube/play/?playlist_id=PLFgquLnL59akhdhcSukD-WMIBEFW53iYT&order=default

reverse order:
Code:
plugin://plugin.video.youtube/play/?playlist_id=PLFgquLnL59akhdhcSukD-WMIBEFW53iYT&order=reverse

shuffle:
Code:
plugin://plugin.video.youtube/play/?playlist_id=PLFgquLnL59akhdhcSukD-WMIBEFW53iYT&order=shuffle