Remote Procedure Call (RPC) isn't MIcrosoft-specific. You'll find many Request For Comments (RFCs) that describe the protocol, its use of dynamic ports, and it binding and authentication.
https://learn.microsoft.com/en-us/windows/win32/rpc/rpc-start-page
This might be a better place to start: https://virtuedesktops.info/port-135/#:~:text=Port-135%20is%20essential%20for%20Remote%20Procedure%20Call%20%28RPC%29,and%20interactions%20between%20computers%20more%20efficient%20and%20seamless.