minecraft_launcher/src/shared/nat-upnp.d.ts

declare module 'nat-upnp' {
  interface PortMappingOptions {
    public: number | { host?: string; port: number }
    private: number | { host?: string; port: number }
    ttl?: number
    description?: string
    protocol?: 'tcp' | 'udp'
  }

  interface UpnpClient {
    portMapping(options: PortMappingOptions, callback: (err: Error | null) => void): void
    portUnmapping(options: { public: number; protocol?: 'tcp' | 'udp' }, callback: (err: Error | null) => void): void
    externalIp(callback: (err: Error | null, ip: string) => void): void
    close(): void
  }

  export function createClient(): UpnpClient
}