I use Inoreader as my RSS feed aggregator of choice. One of the things I have been using it for is to filter my YouTube subscriptions. I would scan the subscriptions and add those I wanted to watch into my watch later playlist by hitting the watch later icon on the video. Well, that is what I did until a couple of days ago when that watch later button disappeared. Now the only way you can add videos to a playlist is to hit the hamburger button below the video and then hit the watch later button. Unfortunately, that hamburger button is not available using Inoreader and appears to be only available directly thru YouTube.