You should not use the low-level api directly. Instead it's advised to utilize the high-level api found
here.
But you will run into a lot of issues if you do that right now, since the game currently has a couple bugs in regards to requesting data. If you don't want to spend countless hours navigating around them, you are better off relying on LibHistoire.
If you still insist on not using it after hearing that, be warned that you will inadvertently interfere with operation of the library and make it slower. So don't blame me when it ends up taking even longer to request data.
