clear_youtube_watch_later.js

(async()=>{
    const wait = async(ms)=>new Promise(resolve=>setTimeout(resolve, ms));
    let btn = document.querySelector('ytd-playlist-video-renderer button[aria-label="Action menu"]');
    while (btn) {
        btn.click();
        await wait(100);
        Array.from(document.querySelectorAll('ytd-menu-service-item-renderer')).filter(it=>it.textContent.trim() == 'Remove from Watch later').forEach(it=>it.click());
        btn = document.querySelector('ytd-playlist-video-renderer button[aria-label="Action menu"]');
    }
})();