Man pages matching name morelabels.hashtbl.hashedtype in section 3o:

MoreLabels.Hashtbl.HashedType.3o.en	debian 10 / ocaml-nox
MoreLabels.Hashtbl.HashedType.3o.en	debian 11 / ocaml-man
MoreLabels.Hashtbl.HashedType.3o.en	debian 12 / ocaml-man