The filename appears to be a pun on the phrase "Ready or Not," likely referring to the tactical first-person shooter game Ready or Not by VOID Interactive. In this context, "Nebo" (Небо) is the Russian word for "sky."
: The mod should load automatically when you start a mission. Ready-Nebo-Not.rar
: Mods for this game are usually packaged as .pak files. The filename appears to be a pun on
: Copy the .pak file and paste it into the game's directory, usually found at: Ready-Nebo-Not.rar
SteamLibrary\steamapps\common\Ready Or Not\ReadyOrNot\Content\Paks
: Graphical mods that replace the default sky textures or lighting profiles to change the atmosphere of existing maps.