view .arcconfig @ 50769:67faf1bd8acd

rust-config: add devel warning when using undeclared config items

This mirrors the Python implementation now that we're done catching up.

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