Deis and Google (as well as others) collaborated on the current v2, building on Google's open source Deployment Manager (which you can see at https://github.com/gabrtv/deployment-manager) - itself derived from Google's Cloud Deployment Manager (https://cloud.google.com/deployment-manager/)
The good thing about open source is, it doesn't really matter who wrote it.
Deis and Google (as well as others) collaborated on the current v2, building on Google's open source Deployment Manager (which you can see at https://github.com/gabrtv/deployment-manager) - itself derived from Google's Cloud Deployment Manager (https://cloud.google.com/deployment-manager/)
The good thing about open source is, it doesn't really matter who wrote it.