2021-04-20 UTC
# ↩️ Activitystreams is startTime/endTime https://www.w3.org/TR/activitystreams-core/#object
Facebook is start_time/end_time https://developers.facebook.com/docs/graph-api/reference/event/
Eventbrite is start/end https://www.eventbrite.com/platform/api#/reference/event
Meetup is actually start/duration https://www.meetup.com/meetup_api/docs/:urlname/events/#list
Google Calendar is start/end https://developers.google.com/calendar/v3/reference/events ( twitter.com/_/status/1384400654031015938)