public class AddInInfo : ArcGIS.Desktop.Framework.Contracts.PropertyChangedBase, System.ComponentModel.INotifyPropertyChanged  

var addin_infos = FrameworkApplication.GetAddInInfos();
StringBuilder sb = new StringBuilder();

foreach (var info in addin_infos)
{
  if (info == null)
    break;//no addins probed

  sb.AppendLine($"Addin: {info.Name}");
  sb.AppendLine($"Description {info.Description}");
  sb.AppendLine($"ImagePath {info.ImagePath}");
  sb.AppendLine($"Author {info.Author}");
  sb.AppendLine($"Company {info.Company}");
  sb.AppendLine($"Date {info.Date}");
  sb.AppendLine($"Version {info.Version}");
  sb.AppendLine($"FullPath {info.FullPath}");
  sb.AppendLine($"DigitalSignature {info.DigitalSignature}");
  sb.AppendLine($"IsCompatible {info.IsCompatible}");
  sb.AppendLine($"IsDeleted {info.IsDeleted}");
  sb.AppendLine($"TargetVersion {info.TargetVersion}");
  sb.AppendLine($"ErrorMsg {info.ErrorMsg}");
  sb.AppendLine($"ID {info.ID}");
  sb.AppendLine("");
}
System.Diagnostics.Debug.WriteLine(sb.ToString());
MessageBox.Show(sb.ToString(), "Addin Infos");