base..ctor();

When you use JetBrains dotPeek to cast CLR to a C# class backwardsly, you may see this inside a constructor like so:

namespace Could.Be.Anything
{
   public sealed class LessAbstract : MoreAbstract
   {
      public LessAbstract()
      {
         base..ctor();
      }
   }
}

 
 

All that means is...

namespace Could.Be.Anything
{
   public sealed class LessAbstract : MoreAbstract
   {
      public LessAbstract() : base()
      {
      }
   }
}