Ephemeral root output values must be kept in the in-memory state representation, but not written to the state file. To achieve this, we store ephemeral root outputs separately from non-ephemeral root outputs, so Terraform can access them during a single plan or apply phase.
Ephemeral root outputs always have a value of null in the state file. This means that the "terraform output" command, that reads the state file, reports null values for these outputs. Consumers of 'terraform output -json' should use the presence of '"ephemeral": true' in such output to interpret the value correctly.
