My bad! I had set the `autoplay` attribute to `"false"`, thinking it wouldn't autoplay. And it didn't, at least in Firefox, but reading the MDN docs for the `v

My bad! I had set the `autoplay` attribute to `"false"`, thinking it wouldn't autoplay. And it didn't, at least in Firefox, but reading the MDN docs for the `video` element, I can see that browsers'll try to autoplay the video if it's present. It's fixed now.