It is a map in ymap format.
Requires installation of additional mods
▶Object Spawn Unlocker
▶Map Builder
▶HeapAdjuster
▶Open IV
▶Increased Props
How to install
1. Drop folder custom_maps to \mods\update\x64\dlcpacks\
2. Using Open IV add a line “custom_maps” to mods\update\update.rpf\common\data
Credits:
Johnny_needs