The Homebridge project provides HomeKit compatibility without Apple authorization. I don't know if Apple controls this using patents or trademarks but you don't technically need Apples authorization.
Homebridge is presumably making use of some debug mode that you wouldn't use in a shipping product - and if you did, Apple wouldn't let you advertise it as officially compatible with HomeKit.
Still neat - but hardly the sort of thing that implies you can ship a product utilizing Homekit without following the MFi spec.