DevOps System.DefaultWorkingDirectory

Hello guys,

New to DevOps, where exactly the predefined variable System.DefaultWorkingDirectory reside ?

Microsoft Docs saying : 

But to be honest, I'm not clear where exactly.

Is it in Repos ? And if I'm using Git Repos so it is mean the root of my Git Repos ?

If I have this code :  $(System.DefaultWorkingDirectory)/$(ArtifactName)/Packages/$(Package)_$(Build.BuildNumber).zip

If lets say I have a variable : ArtifactName = "Test123", so this is mean, I should find that zip file in my Git Repos under root folder / Test123/ Packages /.... ?

Thanks,