RPC plugin is responsible for:
By default, this plugin is configured on the system level by system administrator. You are able to configure your own instance of of the plugin on tenant level. Advanced users or platform developers can customize rpc plugin functionality.
You can specify default RPC timeout for plugin instance in plugin configuration.
RPC plugin API description is available in corresponding rpc guides.
As a system administrator, you are able to review plugin example inside Plugins->System RPC Plugin.