sub-calendar urls

i was reading up on rss feeds, and this is an interesting idea:

https://theeventscalendar.com/knowledgebase/subscribing-to-calendars-via-rss/

URLs for category and tag feeds are generated in the same manner as a standard calendar feed–simply append /feed to the end of any category or tag URL. Our “Tech Meetups” category on our Demo Site is located at https://demo.theeventscalendar.com/events/category/fitness/. Adding /feed to this gives us https://demo.theeventscalendar.com/events/category/fitness/feed and clicking this link will give us a feed of just the events from that category!

it'd be cool to do this with each of our categories, both for the calendar and grid views, and for the calendar feed.

ex. maybe https://www.shift2bikes.org/calendar/21plus/ or https://www.shift2bikes.org/calendar/westside/

Start by tracing how calendar and grid URLs, category URLs, and calendar feeds are currently generated. Use the example 21plus and westside URLs as references, then verify that each category supports the requested calendar, grid, and feed URLs.