Thanks BarryCarlyon, super helpful
RE
An overlay extension in the overlay slot starts open
That’s great news. Though we had a mixed experience on this:
The extension in question is 'FullScreenOverlay" only, Component not enabled.
BUT for the most part it appeared as a thumbnail on the right side of the screen requiring a click to open. Occasionally it opened automatically on page load.
How we tested:
Launching the streamer’s page numerous times during a day of streaming, sometimes logged in to Twitch, sometimes not logged in, and frequently closing the browser window, clearing cache and cookies, and re-launching. We tested using Chrome & Safari on a Mac OS Laptop.
Any reason why we would get mixed results throughout the course of a day?
(We were viewing always on the same channel)
Are there circumstances when a FullscreenOverlay DOES default to thumbnail?