Keeper.sh can now copy a timed event that runs from midnight to midnight as an all-day event. Many subscription links, such as conference schedules, school calendars and sports fixtures, publish a day off that way. It covers the same span of time, but instead of a banner across the top of the day you get a solid 24-hour block.
The setting is per calendar, because the conversion is a judgement: a real event that runs midnight to midnight is rare but possible, and the right answer depends on the calendar you are reading.
Turn it on for a subscription that publishes all-day events as timed blocks, and leave it off for calendars that publish them correctly.
What a copied event shows covers the other per-calendar settings.