Types of cmakelist.txt

I evaluating the following project and I have some questions regarding the cmakelist.txt files that are part t his project.
The structure is the following:


-Subdirectory 1
-subdirectory 2

The first one in subdirectory 1 is pretty standard with all the expected commands like:
cmake_minimum_required(VERSION 3.2…

On the other hand, the second one is totally not standard, at least for me.
It does not start with the cmake_minimum_required command.
Its content is like:


	MODULE examples__app_simple_app
        MAIN app_simple_app

where app_add_module is a function that builds a static library.
My question regards the content of second cmakelist.txt.

Is it possible allowed to write a cmakelist.txt without following the standard structure?
Any help will be highly appreciated.


The CMakeLists.txt in the subdirectory inherits cmake_minimum_required() and project() from the top-level CMakeLists.txt file, through add_subdirectory(). The top-level CMakeLists.txt always has to have these commands, but they are optional in subdirectories.

That’s was fast Kyle.
Clear like water.
Thank you very much