What does it mean to configure Metadata in GCE VM instance (GCE-Ghallenge lab).

Hi all,

I am working on the GCE Challenge lab and in this lab, we are supposed to configure the metadata section as:    and provide the gs:<>/ in the value.   I have difficulty in understanding what "Metadata" section is and how does this configuration instructs the GCE control plane to write to the corresponding GCS bucket and link to the information in the startup script.  Can someone share some pointers to understand what "Metadata" means in the context of GCE Vm instance and its benefits in the context of this lab example?

thank you,

rajesh.