The "plans.filterSet" field from the planCacheListPlans command output is generated by piping a boolean to the cache through the following member variables:

• QueryPlannerParams::indexFiltersApplied
• QuerySolution::indexFilterApplied
• SolutionCacheData::indexFilterApplied

In contrast, the "queryPlanner.indexFilterSet" field for the explain command is supported by directly accessing the QuerySettings for the given collection (which may be out of date).

These approaches should be unified and simplified.