In the meantime I uploaded the videos to peertube.public.cat and they are visible on the agenda. I also updated the slides metadata on HedgeDoc to show rich links, and uploaded @j8ter’s slides as well.
It would be nice to update the participants list and upload the chat log to EC - NGI0 Liaison -- Webinars and Workshop April 2021, @aschrijver would you do it? Maybe use the [details="chat log"] feature to avoid cluttering the page.