2021.12 has removed customization UI and the values can now only by edited in yaml file.
In general, I understand the reasoning, but I also think that UI had two different use cases. At least for me.
The removal reasoning stipulated that those are important values that are not checked and influence state machine etc. I do not fully understand this explanation, but I presume that speaks about changing device_class etc.
But my use-case is mostly ADDING custom attributes and there should be no negative consequences of that for HA as it will just happily ignore them. I then use Node-Red to read them and base my automation behavior on them. For example - I have automation that listens for all state changes of temperature class devices. If such change happens, the automation reads, whether the device has attributes “notify_above” or “notify_below”. If there are such attributes and the current value breaches them, then I get notification. This way I can easily set up notification for any temperatures without any code, I just add the attribute.
Another example is watching for dead devices. I have default notification about dead device when HA has not had an update from it for 2 hours. But if I want to modify the interval, I can just set attribute “dead_for” = 15 and I will be notified after 15 minutes of device inactivity. This is very useful and I would like to have GUI for this back, because editing customization.yaml and restarting HA just sucks.
This should be safe for HA.
Thanks for considering.