Top bar & Watch later
Both need a signed-in account, so they appear only when you’re signed in.
Settings in top bar
Section titled “Settings in top bar”A gear button sits before your avatar and opens YouTube’s settings. The Settings entry in the sidebar goes away.
The switch is Navigation → Settings in top bar, with no options.
Kempt inserts a link to /account in the top bar’s end slot (ytd-masthead #end). The tooltip follows YouTube’s UI language.
Watch later button
Section titled “Watch later button”A Watch later button sits in the action row under the video. Click it to add the video to Watch later; it fills in. Click again to remove it.
The switch is Navigation → Watch later button, with no options.
The button asks the page bridge for two things:
inWatchLater(id)loads the video’s playlist state with the request YouTube’s Save menu sends (playlist/get_add_to_playlist), so the button starts filled when the video is already saved.setWatchLater(id, on)adds or removes the video withbrowse/edit_playliston theWLplaylist.
Both run in YouTube’s page with your session and sign their requests the way YouTube signs its own.
Limits
Section titled “Limits”- If YouTube changes how it signs these requests, the button stops working until Kempt is updated. The Save menu keeps working either way.