Nothing happens - either the error report is not sent, or the fact that it was sent is not conveyed to the user.
Reproduced three times in a current Chromium version (Chromium/25.0.1364.160) on Ubuntu.
Version: unspecified
Severity: normal
The reports go to a private log that Gabriel monitors. :-)
We're likely to kill the feature in the medium-term anyway, but a "Thank you for your report" JS alert wouldn't go amiss.
Timo, thoughts?
IIRC posting from Wikipedia pages accessed via https has always been broken because of client-side security restrictions for subrequests. I think this is an instance of that problem.
To clarify, Gabriel checked the log and the reports I sent indeed do not seem to have made it through.
And I agree that a "thank you" alert would be nice, but I would already have been happy if the "Report a problem" dialog box would just have closed after clicking the "Report problem" button. Instead, nothing happened at all...
The HTTPS element of this is now seemingly fixed in production. On submission, the user gets a "Your problem has been reported. Thank you." message. Marking as closed.