It’s actually easier than that. If you want to contribute to the app i’m not the best person to ask, but you can download the app, add the code and use your version of the app instead.
Download the app at Github and follow this tutorial:
Go to drivers/device name/driver.compose.json and add the info of your device at “manufacturerName” and “productId”.
This will only work if the device has been added to the app, just not your device code.
You can get those IDs by adding your device ad generic zigbee device and looking at homey developer site
