Man pages matching name polytype_atex_mask in section 3alleg4:

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