The Virtual Kubelet Helm chart
Each version of Virtual Kubelet has a dedicated Helm chart. Those charts are served as static assets directly from GitHub.
The index.yaml file
This subdirectory has an index.yaml file, which is necessary for it to act as a Helm chart repository. To re-generate the index.yaml file (assuming that you have Helm installed):
cd /path/to/virtual-kubelet
helm repo index charts
The index.yaml then needs to be committed to Git and merged to master.