Constructing the URL for the build downloads

Hi,

I'm trying to construct the build downloads URL , so that ATN task can download it and keep it in target folder as part of the build.

When I see the URL of downloadable , I get following URL

https://localhost:9443/jazz/resource/virtual/build/result/_4U5P0D0cEeGJXM_NjRHg0w/contribution/_WDb8UD0dEeGJXM_NjRHg0w/download.war

where
_4U5P0D0cEeGJXM_NjRHg0w : item type of ${buildResultUUID}

but what is item type of "_WDb8UD0dEeGJXM_NjRHg0w" , that comes after contribution in the URL ?

How does it relate to build , so that it can be used in constructing URL of the resulting downloads of the builds.