Unrelated to the content of the video - is it possible to remove French voice-over?
EDIT: I guess only option is to download the video file and switch the audio language as browser's player cannot do this.
EDIT2: from html - there are multiple sources, english is the first one, though player starts automatically from the second source. Link to english video: https://koeln.ftp.media.ccc.de//congress/2019/h264-hd/36c3-1...
EDIT3: after couple reloads and waiting couple dozen of seconds native html video player have switched to some custom CCC player with settings option available. Probably needed some time before JS fully loaded and did it's job. Apparently /u/lovehashbrowns had loading issues, so this sounds related. Maybe CCC is getting hug of death from HN, Reddit or whatever.