What Namespace is the Default attribute for properties on UserControls?

I found half of the answer here to my question when searching "what is the attribute to set the default value of a User Control property in the designer where you change it and it bolds".

However the answer neglects to mention the namespace it is in.

Searching through Object Browser yields hundreds of classes/properties with the name Default in it. Google seems to bring up DefaultProperty attribute for ASP.N开发者_Go百科ET, and the MSDN article neglects to mention this ability.

Since I can't find the answer on Google, MSDN, Visual Studio, and using VB.NET does not put the namespace it is in by default, I shall put forth the question.

What namespace is it in?

If it's in System.Windows.Forms, what assembly do I need to reference?

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You're looking for System.ComponentModel.DefaultValueAttribute.