SponsorBlock is a crowdsourced extension to skip sponsor segments in YouTube videos.
DeArrow is a crowdsourced extension to replace titles and thumbnails on YouTube videos with more accuracy and less sensationalism.
News: https://sponsor.ajay.app/news
Created by Ajay (https://ajay.app)
@Atemu @kagihq looks like they are using the same method as the clickbait remover extension which is using one of the three auto generated thumbnails created by YouTube when a video is uploaded
The downside is their thumbnail algorithm looks for faces, as you can see in their example screenshot