Man pages matching name qscale_matrix in section 3alleg4:

qscale_matrix.3alleg4.en	debian 10 / allegro4-doc
qscale_matrix.3alleg4.en	debian 11 / allegro4-doc
qscale_matrix.3alleg4.en	debian 12 / allegro4-doc
qscale_matrix.3alleg4.en	debian 13 / allegro4-doc