What is the Category and Description incode?

hi;
What is the order of Category and Description in the following code?
What it does?
plead Help me.
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private class NodeProps
  {
  [Category("Properties")]
  [Description ("The text displayed within the node.")]
  public string Text
  {
  get { return _text; }
  set { _text = value; }
  }
 
  [Category("Properties")]
  [Description("The font of the node's text.")]
  public Font Font
  {
  get { return _font; }
  set { _font = value; }
  }
 
  [Category("Properties")]
  [Description("The interior color of the node.")]
  public Color FillColor
  {
  get { return _fillColor; }
  set { _fillColor = value; }
  }
 
  private string _text;
  private Font _font;
  private Color _fillColor;
  }
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