It seems the Koogeek app allows you to retrieve lost HomeKit codes - but only for its own devices. : r/HomeKit
Wi-Fi Enabled Smart LED Light Bulb - Koogeek.com
KooGeek SMART Dimmer - YouTube
Koogeek Wi-Fi Enabled E27 8W Color Changing Dimmable Smart LED Bulb Works with HomeKit Support Siri Home App Schedules Remote Control 16 Million Colors AC200-240V - Walmart.com
New from Koogeek: WLAN light switches and dimmers for HomeKit
HomeKit Light Switches & Dimmers - Review
Smart 3 Way Dimmer Light Switch Kit, Meross 2.4GHz WiFi Dimmer Switch for Dimmable LED Light, Halogen and Incandescent Bulb, Support Alexa, Google Assistant and SmartThings, Remote and Voice Control - - Amazon.com