Safari cannot currently play OGG or WEBP format videos in the Quickview panel. The file information and thumbnail loads, but the video.js player fails with the message "No compatible source was found for this media."
If the user clicks through to the relevant File page, however (where the older player is still used), the video is now playable.
According to @brion, the new player may need to engage the ogv.js shim to handle these formats, which may involve re-arranging some RL modules.
This problem likely impacts all versions of both Desktop and Mobile Safari.
Developer notes
ReferenceError: fixedTimeID is not defined https://logstash.wikimedia.org/app/dashboards#/doc/logstash-*/logstash-2021.05.05?id=UvzUPXkBA6MeBtBq6sz9