You can use the title_template argument for that the default is “{{date.summary}}” but you can add any of the following variables in the string like that:
date.id, date.summary, date.description, date.start, date.end, date.all_day, date.transparent, date.recurring, date.location, date.private, date.created, date.last_modified, date.sequence, date.recurrence_id, date.attendee, date.organizer, date.categories, date.floating, date.status, date.url
But parsing them with the generic ICS source sounds pretty bad, so it’s probably best to write a dedicated source for mzv Rotenburg
I wrote a source here: add Source for MZV Rotenburg Bebra by 5ila5 · Pull Request #3107 · mampfes/hacs_waste_collection_schedule · GitHub
