Man pages matching name scene_gap in section 3alleg4:

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