Man pages matching name object_message in section 3alleg4:

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