What is the "windows_subsystem" `cfg_attr`

[orchid harness]

Every example project is generated with

#![cfg_attr(
    all(not(debug_assertions), target_os = "windows"),
    windows_subsystem = "windows"
)]

at the very beginning, and i can't tell why or what it's supposed to do.
The docs don't seem to ever talk about it, and I'm wondering why it's added there and if i can just remove it.

I know it's seemingly setting a preprocessor variable (windows_subsystem) to "windows" for Windows Release
But i have no clue why

[tribal ore]

See https://doc.rust-lang.org/nightly/reference/runtime.html#the-windows_subsystem-attribute.