Man pages matching name al_detach_sample_instance in section 3alleg5:

al_detach_sample_instance.3alleg5.en	debian 10 / allegro5-doc
al_detach_sample_instance.3alleg5.en	debian 11 / allegro5-doc
al_detach_sample_instance.3alleg5.en	debian 12 / allegro5-doc