How does a registrar update the gtld name servers?

How does a registrar update the gtld name servers?

Is there a standardized protocol how a registrar updates the NS
information for a domain? For example, if, through my registrar's
interface, I set the name servers for "example.com" to "ns1.example.com"
and "ns2.example.com" how are [a-m].gtld-servers.net updated with this
information? Does this protocol use the whois information or is that
merely informational for the end user?
Edit: I see rfc3375 "Generic Registry-Registrar Protocol Requirements" but
that is informational.