Fullstory integration

I was wondering if anyone has successfully integrated Cesium with Fullystory’s screen captures? Right now when the user loads the Cesium scene, it is just a gray scene

I’m not familiar with FullStory - is this it? https://www.fullstory.com/

Do you know if they support WebGL content generally? Does it work with other 3D content on the web, or say, if a user was interacting with a YouTube video?