I use the Firefox app on an Android phone and I've renamed the device to "Samsung Galaxy A50". When I use Firefox on my computer if I click on the "Show tabs from other devices" button instead of my custom name it shows a default name with the model number. "Send Page to Device" does display the personalized name. I've tried logging off from the Android app and logging in again. The custom name appears for a few hours but then reverts to the default name again.