Right now not all Serving deployments have a readiness, liveness probe and we only support probes configuration for the ones that have one. In other words, we dont allow the user to add a probe. The engineering work related to this doc issue will add readiness, liveness probes to all related Serving deployments as K8s best practices recommend to have such probes (Eventing seems to have done that).

If the engineering work does not make it in 1.28 or we omit some deployment for some reason, we will need to add in the section here https://docs.openshift.com/container-platform/4.11/serverless/admin_guide/serverless-configuration.html#knative-serving-CR-system-deployments_serverless-configuration which deployments does not support probe overrides. Otherwise we will not need to document anything the Serving example we have in the docs (previous link) needs no addition info.