detective wanted: how is this company able to create instant transcripts for free?

Does anyone have an idea as to how https://chromewebstore.google.com/detail/youtube-summary-with-chat/nmmicjeknamkfloonkhhcjmomieiodli

is able to generate near instant transcripts for 3 hour videos for free?

I've tested it on 2 hour+ videos with 50 views so I doubt the transcripts are being cached. I also don't know how this can be done for free considering most video to transcription services cost around $1.5 per hour and given that it works on YouTube videos that don't even have a native transcription button.