Offline expressions are simple C# expression, that are configured on the server, but evaluated on the client. An offline expression has to be enclosed in curly brackets and a code tag. The following example code would could be used for the Initial Value of a string MetaProperty, and it would write the value of the property NAME into the initial value of the given property, when an instance of the carrying MetaClass is created on the client:
{code:ParentLevel["NAME"]}