Man pages matching name get_x_rotate_quat in section 3alleg4:

get_x_rotate_quat.3alleg4.en	debian 10 / allegro4-doc
get_x_rotate_quat.3alleg4.en	debian 11 / allegro4-doc
get_x_rotate_quat.3alleg4.en	debian 12 / allegro4-doc