Man pages matching name al_register_sample_loader in section 3alleg5:

al_register_sample_loader.3alleg5.en	debian 10 / allegro5-doc
al_register_sample_loader.3alleg5.en	debian 11 / allegro5-doc
al_register_sample_loader.3alleg5.en	debian 12 / allegro5-doc
al_register_sample_loader.3alleg5.en	debian 13 / allegro5-doc