.arcconfig

import: suppress accept: header

irccloud and others may perform content negotation and reject (406)
if the accept header does not match the mime type of the object

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}