I agree with this. Although I would probably make it a pseudo file system and allow normal file reading (you want to dump as JSON? Read /etc/conf/app.json. TOML

I agree with this. Although I would probably make it a pseudo file system and allow normal file reading (you want to dump as JSON? Read /etc/conf/app.json. TOML? /etc/conf/app.toml) as well as something like sysfs (/etc/conf/app/thing). The raw data itself can live at /mnt/conf. The thing I'm not sure about is how you'd implement secure initialization/registration of a new app on first run.