Donc comme écrit, ils le font payer par souscription :
Subscription Required
As of May 2025, homebridge-gsh requires a subscription to operate. This change supports the maintenance of the secure cloud infrastructure that enables integration with Google Smart Home. New users will receive a 7-day free trial. Existing users will be gradually enrolled starting in mid June 2025.
For more details on pricing, enrollment, and frequently asked questions, please visit the Subscription Service wiki page.