Jean-François or as I know him as Jeff is a Sitecore MVP. He works at Coveo as a Sitecore Developer. Coveo is a powerful search engine with machine learning on the cloud.
It has a number of integrations as seen here. One of the integrations is with Sitecore. I've had the pleasure to be taught by Jeff at a Coveo for Sitecore certification.
Jeff did a Coveo on Sitecore deep dive from start to finish. He is very knowledgeable about Front-end technologies. He is also on twitter @jflh. If you need more information about Coveo I recommend reaching out to him.