Once the project has been completed and the docs page for $rankFusion published, reach out to the appropriate docs teams to get the stable link for the $rankFusion docs page. Replace the technical design document link in the Search README under the scoreDetails Technical Overview with this docs link.

This one should be ready now that 8.1 docs are public: https://www.mongodb.com/ja-jp/docs/rapid/reference/operator/aggregation/rankFusion/