IDRB data identifies the component that created the program module. IDRB data is associated with the entire module never in individual sections.
IDRL data is produced by the language translator and identifies the compiler or assembler that produced the module or section and the date of compilation.
IDRZ data is created by AMASPZAP when it is executed against program modules. It contains a maintenance identifier (such as PTF number) and the date that the maintenance was applied.
IDRU data is provided by the user on the IDENTIFY control statement for a program module. It can contain any information pertinent to the associated section. It is created at bind time using the IDENTIFY control statement. See IDENTIFY statement for more information.