Besoin d'explication

Private Sub CommandButton1_Click()
Dim L As Integer
Dim i As Integer
Dim Nom As String
Dim Msg As Byte
Nom = ComboBox1.Value
If Nom = "" Then Exit Sub
Msg = MsgBox("Voulez-Vous Ajouter : " & Nom, vbYesNo)
    If Msg = 6 Then
        L = Sheets("Feuil1").Range("A65536").End(xlUp).Row + 1
        Sheets("Feuil1").Range("A" & L).Value = Nom
        Sheets("Feuil1").Columns("A").Sort Key1:=Range("A1"), Order1:=xlAscending, Header:=xlGuess
        For i = Range("A65536").End(xlUp).Row + 1 To 2 Step -1
        If Range("a" & i) = Range("a" & i - 1) Then
        MsgBox "Doublon Détecté et Détruit : " & Range("a" & i - 1).Value, vbCritical
        Range("a" & i).ClearContents
        End If
        Next
        On Error Resume Next
        Sheets("Feuil1").Columns(1).SpecialCells(xlCellTypeBlanks).EntireRow.Delete

    End If

End Sub

If Msg = 6 Then