copies: add a devel debug mode to trace what copy tracing does
Mercurial can spend a lot of time finding renames between two commits. Having
more information about that process help to understand what makes it slow in
an individual instance. (eg: many files vs 1 file, etc...)
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}