Project ID of the project you're trying to access. To find the ID of the project, make a call to /api/projects/.

Human-readable name for the holdout group.

Optional description of what this holdout reserves and why.

Non-empty list of release-condition groups defining the held-out population, using the same shape as feature-flag release conditions. Each element's `rollout_percentage` (0–100, may be fractional) is the **exclusion** percentage — the share of users held back from all experiments that reference this holdout. `properties` optionally narrows the group by person/group properties. Do not set `variant`: the server normalizes it to `holdout-{id}`. Note that only the first element's `rollout_percentage` is embedded into each linked experiment's feature flag, and this population is shared across every experiment using the holdout.

The effective access level the user has for this object