public sealed class DefaultValueAttribute : System.Attribute

Sometimes with CodeGen we want reflection to be able to get the original initial value of a property (which is set with {get;set;} = initialvalue;). For this reason sometimes we'll drop this attribute on that property. You might want to use this manually for instances where codegen can't define the default value. This will usually happen for structs like vector and color.. if the default value isn't defined as a number or string.