Delphi what methods will get into RTTI?

Question

Delphi

Good afternoon!
I'm interested in the principles by which methods are submitted to RTTI. We are talking about the "old" RTTI (before Delphi 2010 or in the current FPC). As far as I understand at the moment, all fields from the published section should get into RTTI, apparently this is not the case.
Now there is a code:

{$M+}
  TMyClass = class	
    published
      procedure testfn(a,b,c: Integer);
  end;
{$M-}
...
GetPropInfo(TMyClass, 'testfn'); // возвращает nil

I would like to understand what needs to be changed in order to get the PPropInfo for the method.