function load_sponsorblock(){
  const info_elem = Q('#skip_n');
  if (info_elem.innerText.length) return;  // already fetched
  const hash = sha256(data.video_id).substr(0,4);
  const video_obj = Q("video");
  let url = `/https://sponsor.ajay.app/api/skipSegments/${hash}?service=YouTube&categories=%5B%22sponsor%22,%22selfpromo%22%5D`;
  fetch(url)
      .then(response => response.json())
      .then(r => {
    for (const video of r) {
      if (video.videoID != data.video_id) continue;
      info_elem.innerText = `(${video.segments.length} segments)`;
      const cat_n = video.segments.map(e=>e.category).sort()
          .reduce((acc,e) => (acc[e]=(acc[e]||0)+1, acc), {});
      info_elem.title = Object.entries(cat_n).map(e=>e.join(': ')).join(', ');
      for (const segment of video.segments) {
        const [start, stop] = segment.segment;
       if (segment.category != "sponsor" && segment.category != "selfpromo") continue;
        video_obj.addEventListener("timeupdate", function() {
          if (Q("#skip_sponsors").checked &&
              this.currentTime >= start &&
              this.currentTime < stop-1) {
            this.currentTime = stop;
          }
        });
      }
    }
  });
}