`?file_prefix:[ `Allowed | `Not_recognized | `Required ] ->
?host_prefix:[ `Allowed | `Not_recognized | `Required ] ->
?system_encoding:Pxp_core_types.I.encoding ->
?map_private_id:(Pxp_core_types.I.private_id -> Neturl.url) ->
?open_private_id:(Pxp_core_types.I.private_id ->
Pervasives.in_channel * Pxp_core_types.I.encoding option) ->
?base_url_defaults_to_cwd:bool ->
?not_resolvable_if_not_found:bool -> unit -> Pxp_reader.resolver`