It is a feature provided by Route 53 to keep health checks and you can create it also.
The health check basically keeps track of specified resource
Keeps you updated with the status of your resource
Tracks the CloudWatch Alarm
You can view the health status in the Route 53 console, you can configure CloudWatch Alarm if you want to get a notification for the same.
You can see the details on how to create a Health Check here:
https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/health-checks-creating-deleting.html