I noticed that when no router is available several projects use 192.168.4.1 as the default IP address. The device offers a a web server to allow configuration.
Why isnt the device using Automatic Private IP Addressing which would get a 169.254.x.x address?
The code is in the libraries. This range also seems a good place for sensors that should never be accessed from the internet. This range is not forwarded by routers.
Is there a good reason to have sensors accessible when you could pass just the data via say a MQTT broker?