Preview phase for settings that are feature previews.
For settings that are not feature previews, the preview_phase field is left unset.
Mirrors only the customer-facing phases surfaced in the UI; internal-only phases
(DISABLED, DEV, UNDER_MIGRATION, LAUNCHED, etc.) are not exposed here.
Preview phase for settings that are feature previews. For settings that are not feature previews, the preview_phase field is left unset. Mirrors only the customer-facing phases surfaced in the UI; internal-only phases (DISABLED, DEV, UNDER_MIGRATION, LAUNCHED, etc.) are not exposed here.