You can view Rate Limiting analytics in the Analytics app of the Cloudflare dashboard. To see the Rate Limiting panel in the UI, you might need to scroll down.
This panel shows information about the number of requests that match a rule and that received a 429 error (i.e. blocked), which Cloudflare Rate Limiting delivers to clients that exceed the rule limit. This status code is not Cloudflare-specific and is used by some origins, too.
The graph shows traffic that matched the rule for both simulated and blocked requests. The solid line indicates all requests, while the dotted line shows blocked requests.
Enterprise customers can additionally see a breakdown of blocked requests per location in their status code analytics view, as 429 statuses indicate that a rule blocked a request (but it also includes 429s from the origin if your origin returns them).