* python-crcmod is pulled in from backports as it provides a compiled crcmod required for the Google Cloud Storage CLI (gsutil).
* cloud-utils and cloud-guest-utils are pulled in from backports as they provide a fixed version of growpart to safely grow the root partition on disks >2TB.
* google-cloud-sdk is pulled from a Google Cloud repository.
* google-compute-engine is pulled from a Google Cloud repository.
The only additions are the necessary google-compute-engine, google-compute-engine-init, and google-config packages. This image is not published on GCE however the manifest is provided here for those wishing a minimal GCE Debian image.