what is the default grafana setting for $__rate_interval

[Devadrita Bose]

I understand that rate(xyz[5m]) * 60 is the rate of xyz per minute, averaged over 5 mins.

1. How then would $__rate_interval and $__interval be defined, possibly in the same syntax?
2. What format is rate being measured here, in my panel? Per minute, per second?
3. What is the interval= 30s in my panel here? My scraping interval is set to 5s.
4. How do i change the rate format?