Client vs. server feature
Client feature
A client feature has a different value for each user of the application. Each user will see the default value but they can update it at anytime (default behavior).
var themes = new List<string>{ "light", "dark"};
configuration.ClientFeature("Theme", themes[0], "Choose a theme for the frontend", themes);
Server feature
A server feature is defined globally and it will have the same value for every user of the application.
configuration.ServerFeature("Beta", true);
Server features are often only managed by an admin.