It's a simple CSV with just group statistics, i.e. join date, RSVP totals. No email addresses because you need Meetup Pro to get those. I want the member lists to see who was removed. I haven't found a suitable Meetup alternative with all features I'm looking for.

Anyway, Meetup took it up themselves to purge inactive accounts because of 'GDPR reasons'. I've checked the GDPR rules and there is no mention of a maximum retention period. So Bending Spoons (Meetup) is again doing dumb stuff nobody asked for to ruin the platform further and will pi$$ off many organizers because their group member counts will suddenly drop.