A comma delimited list of Facebook event fields which need to be retrieved by the Facebook event Graph API. The full list of available fields can be found in Facebook event API documentation
facebook.event-fields=id, category, cover, description, type, end_time, is_page_owned, can_guests_invite, guest_list_enabled, name, owner, place, start_time, ticket_uri, timezone, updated_time, attending_count, declined_count, maybe_count, noreply_count, interested_count
Crawling Facebook events is only possible if the
facebook.access-token property is specified with a never expiring page access token.