Looks like this is a policy-as-code tool in the vein of Terraform Cloud's Sentinel Policies, or more generally Open Policy Agent, but specifically targeted at k8s use cases.

From the custom rules overview https://hub.datree.io/custom-rules-overview , though it is docs WIP, I noticed these are defined as YAML/JSON somehow. That's a contrast to HashiCorp's Sentinel https://docs.hashicorp.com/sentinel/concepts/language and OPA's Rego https://www.openpolicyagent.org/docs/latest/policy-language/ . Is this an intentional design decision?