This is a great use of the sidepanel API. Really like the idea and how you implemented it. The Firefox equivalent to that API isn’t identical to Chrome’s, and I believe that there is currently no way to trigger the side panel to open programmatically unless it’s in response to a user action. So it may take a bit of work, but would be exciting to see support for FF in the future.
A bit tangential but I was curious what you used to record the demo video on your landing page with those zoom-in animations during critical moments. I’d like to record something like that for some of my side projects and thought your video looked rather polished.