https://www.cnet.com/news/apple-homekit-everything-you-need-to-know/

You might not know it, but you're using Apple HomeKit every time you issue a smart-home-related voice command on your iPhone, HomePod -- or other Siri-compatible device.

HomeKit is to Apple what Alexa skills are to Amazon, or what actions are to Google. It's that intangible, but vital in-the-background software that makes it possible for you to turn on your smart lights every morning with a simple Siri command (or from Apple's iOS-only Home app).