What is the meaning of the advanced language settings? Should auto-detection work without clicking that button?

[Ceres]

Hello!

What is the meaning of the advanced language settings?

For US and GB English, it is straightforward:

 

For German, the advanced settings look as follows after I selected German from the non-advanced menu:

I wonder about the "Land" (country) codes:

What do they mean? 001, 150, 419, and the following 2-letter codes? For German, I am familiar with maybe a handful of codes for other countries where German is partly used, but the list here is very long. What exactly for?

Furthermore, only when I explicitly click on "Autoerkennung" (automatic detection), the language scheme is changed from de_001 to de_de. Is this as intended, or should the auto-detection be triggered automatically (without clicking the button)?

And what is the script field about?

Thanks for helping me better understanding this.