The plugin's own declared default DomainRules for the domain(s) it targets.
Absent/empty means the plugin declares no concurrency/rate-limit defaults of its own — that
domain is unmanaged (unlimited) unless a user override exists (spec FR-017: the system itself
imposes no default).
Usage
import { type PluginOptionsResult } from "crates/lanrurugi-plugin/dispatcher/plugin-sdk.ts";