When creating a new event via Stryd's mobile app, you must assign a 'Priority' to the event: A, B, or C. This is a feature that is tied to future development and will help determine how an event is associated with future training plans.
For now, giving events different priority levels will give them a different race card and helps you quickly identify and differentiate upcoming races.
For future purposes:
'A' events are your primary event. This is the event you associate with a training cycle and usually comes at the end after a good taper period to achieve your best results.
'B' events are secondary events that help to gauge the effects of your training and your race readiness as your 'A' event approaches.
'C' events are your fun runs. These events take less priority and are typically not done at max effort and might be thrown in throughout your training cycle.