Hook name: $returned_one Hook type: filter Plugin ref: WordPress develop tests Sourcefile: File ref: Tests_WP_Hook_Apply_Filters::test_apply_filters_with_multiple_calls() – Description: Parameters: Deprecated?: No API Letters: $,O Invokers 1 to 1 of 1 Tests_WP_Hook_Apply_Filters::test_apply_filters_with_multiple_calls() – Implementers