Experiment Rule
An experiment rule that links a feature value to an existing experiment.
Must be "experiment-ref" for an experiment rule.
Allowed value:
"experiment-ref"ID of the linked experiment.
When true the rule applies to all environments. Defaults to false.
Specific environment IDs this rule applies to. Used when allEnvironments is false.
JSON features only. When true, each variation value is a partial object merged onto the feature's default value instead of replacing it.

