This file is a compressed RAR archive. Based on the naming convention:
: Often refers to SMC Networks (a manufacturer of routers, switches, and modems) or specialized "SMC" (System Management Controller) software. sc13356-SMCVINFPPUpd10129.rar
unless you are certain it matches your specific hardware model and version. Applying incorrect firmware (known as "cross-flashing") can permanently "brick" your device, making it unusable. This file is a compressed RAR archive