Man pages matching name xcb_randr_set_provider_output_source in section 3:

xcb_randr_set_provider_output_source.3.en	debian 10 / libxcb-doc
xcb_randr_set_provider_output_source.3.en	debian 11 / libxcb-doc
xcb_randr_set_provider_output_source.3.en	debian 12 / libxcb-doc