Eliom_extensionAllows Ocsigen's extension to access Eliom data. See the Eliom manual for more information about <<a_manual chapter="workflow-configuration"
fragment="extensions"| Eliom's extensions>>
type eliom_extension_sig = unit -> Ocsigen_extensions.answer Lwt.tType of the function that must be registered to declare an eliom extension.
val register_eliom_extension : eliom_extension_sig -> unit