Speaking of features which are sparse in documentation. There is an intersting and a bit useless feature in dynamic arrays laying around: array constructors.

Let’s check out this example:

type
  TMyArray = array of Integer;

var
  X: TMyArray;
begin
  X := TMyArray.Create(1, 2, 3);

  WriteLn(Length(X));
  ReadLn;
end;

This code will actually compile and run.
(May probably be a remnant of old .NET days)