Cannot display extended diagnostics
I've suddenly found that I can no longer display the extended diagnostics panels for any of my hosted Perch or Runway sites. I can't recall the last time I checked one of them, so can't tell from when this happened. The problem is happening on all Perch sites (3.1.1 or 2.8.34) and Runway sites (3.1.1 or 3.0.11), so my suspicions are that something's changed at the hosting that is causing this.
For Perch sites, a URL containing /core/settings/diagnostics/ works fine but /core/settings/diagnostics/?extended produces a 403 Forbidden error and 'You don't have permission to access /perch/core/settings/diagnostics/index.php on this server.'. For Perch Runway sites, a 404 error is displayed.
Can you tell me what /?extended is doing that might be causing the problem so I can narrow down the cause and fault?