USG at least supported json files for some customization. This was necessary as the Network application was lacking several desirable features and json customization allowed some of them to be implemented even if they were not manageable in the GUI.

These new routers do not support json which was a shock for those upgrading from the USG when they found their json customizations no longer worked. The somewhat redeeming point here is that a lot of requested features (for example, WireGuard or OpenVPN client/server support) have been added to the Network application GUI so the need for json support has been reduced.



I imagine support was sometimes challenging with json customizations.