SERVER-85426 removed all the hybrid search feature flags, but the operators $sigmoid, $minMaxScaler, $rankFusion, $scoreFusion, and $score were deliberately kept out of the Stable API (AllowedWithApiStrict::kNeverInVersion1) to avoid making a permanent V1 commitment as a side effect of flag removal.

This ticket tracks confirming which (if any) of these should be promoted and updating the registrations and tests accordingly.