I pressed the “play animation” button, and the fox disappeared and nothing else happened. If I hadn’t had video autoplay disabled, the fox would just not have been visible in the first place.
> Media resource https://assets.mozilla.net/video/kit/pop-up-800.webm could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_FATAL_ERR (0x806e0005)
> Details: auto mozilla::MediaChangeMonitor::CreateDecoderAndInit(MediaRawData *)::(anonymous class)::operator()(const MediaResult &) const: Unable to create decoder
Unfortunate.
(firefox-nightly, Linux.)