https://www.racedepartment.com/downloads/top-center-flags-for-vr.17416/
Just copy your specific flags folder to \....\Steam\steamapps\common\assettocorsa\content\gui
and replace the default flags folder.
The pack depends on your monitor (or downsampled) width resolution:
- RESOLUTION=1920x1080 choose 1920p pack; etc
