If you're looking for a Chrome extension to get a quick look at YouTube videos, YouTube Summary with ChatGPT is a good choice. The free extension uses ChatGPT's large language model to generate a summary as soon as you load a YouTube video, so you can quickly get a sense of what's going on without having to watch the whole thing. It's geared for researchers, students and others who have to consume lots of video.
Last, YTSummary offers detailed summaries of YouTube videos with features like segment mode and summary export. It works with multiple languages and offers a free plan with 10 credits, so it's good for light use. Paid plans offer more features like unlimited summaries and priority customer support, so it's good for heavy use, too.