For technical reasons there are UCR variables that mirror a corresponding app setting unidirectional, meaning that the only supported and working interface is the app setting and the UCRV must not be used. From a users perspective this is rather confusing because we promote UCR as a unified configuration interface for all purposes and with explicitly providing a key we give them reason to believe that this should be working. What we should do instead is at least make it clear when using these UCRVs that this is not the supported way of changing things and it will not work, f.e. with adapting the description or giving out a warning. Even better would be if we would prevent these from being used, f.e. by hiding the keys from user interfaces, making them hidden technical features or by preventing them from being set by a users interaction.