Is your feature request related to a problem?

The event calendar view already colors events based on their category. There is no way, however, to know which category the events belongs to.

Describe the solution you'd like

Add a vertical legend on the sidebar displaying all the categories present in the current month, alongside their assigned color.

Additional context

The legend in the event calendar view is a stepping stone to a number of improvements, like adding event coloring by location and filtering events in the calendar by category/location.

This feature request comes inspired by Perimeter Institute's in-house developed calendar view: