I believe (although I haven't verified) that this is a "more breaking" change than what's in Phabricator HEAD (which may fail server-side integrations and remove information from the UI, but won't generally affect "arc"), so maybe hold this for a bit. But whatever. I believe the number of installs affected by this is very small (and maybe even 1 or 0) and we've never documented or recommended this mechanism since it has been on the chopping block for years.