Umbraco-CMS/umbraco/cms/businesslogic/installer/IInstallerStep.cs

using System;
namespace umbraco.cms.businesslogic.installer
{
    interface IInstallerStep
    {
        string Alias { get;}
        bool Completed();
        string Name { get;}
        string UserControl {get;}

        string NextButtonText { get; }
        string NextButtonClientSideClick { get; }
    }
}