Filesystem:/Applications/iOS Diagnostics.app

Summary
This (hidden) application is usually used at the Genius Bar in Apple Stores. It sends diagnostic data of a device to a Genius' iPod touch/iPad running iOS Diagnostics. It is present on all iOS 5+ devices, but on iOS 8.3+ devices /Applications/Diagnostics.app is usually used instead of this.

It sends data about the device to https://iosdiags.apple.com/MR3Server/MR3Post. The URL schema that it utilizes is, where is the support ticket number given to them by Apple over the phone to allow them to send their device's data over to Apple.

Localization strings
Extracting its English localization strings yields these:  /* Privacy Information */ "By clicking “Send to Apple” you agree that Apple may periodically collect diagnostic data from this device, including the device serial number, device name and daily count of call attempts. This data will be used to troubleshoot issues with your device and to improve our products and services. For information on Apple’s Privacy Policy, see http://www.apple.com/legal/privacy." = "By clicking “Send to Apple” you agree that Apple may periodically collect diagnostic data from this device, including the device serial number, device name and daily count of call attempts. This data will be used to troubleshoot issues with your device and to improve our products and services. For information on Apple’s Privacy Policy, see http://www.apple.com/legal/privacy.";

/* Cancel */ "Cancel" = "Cancel";

/* Done */ "Done" = "Done";

/* App Title */ "iOS Diagnostics" = "iOS Diagnostics";

/* Last Sent: */ "Last Sent:" = "Last Sent:";

/* Never */ "Never" = "Never";

/* Next */ "Next" = "Next";

/* OK */ "OK" = "OK";

/* Send to Apple */ "Send to Apple" = "Send to Apple";

/* Sending to Apple... */ "Sending to Apple..." = "Sending to Apple...";

/* Ticket number is not valid error message */ "The ticket number was not found. Verify the number and try again." = "The ticket number was not found. Verify the number and try again.";

/* Submission error message */ "There was an issue with your submission. Please make sure you are connected to the internet and try again." = "There was an issue with your submission. Please make sure you are connected to the internet and try again.";

/* Ticket Number Placeholder */ "Ticket Number" = "Ticket Number";

/* Ticket Number: */ "Ticket Number:" = "Ticket Number:";

/* Ticket validation server is unavailable error message */ "Ticket validation has failed. Please make sure you are connected to the internet and try again." = "Ticket validation has failed. Please make sure you are connected to the internet and try again.";

/* Enter Ticket Number */ "To receive support services, enter the ticket number you were given." = "To receive support services, enter the ticket number you were given.";

/* Submission success message */ "Your information has been received by Apple." = "Your information has been received by Apple.";

Reference
Analysis on MacRumors forums

Folders

 * Dutch.lproj/
 * English.lproj/
 * French.lproj/
 * German.lproj/
 * Italian.lproj/
 * Japanese.lproj/
 * Spanish.lproj/
 * _CodeSignature/
 * ar.lproj/
 * ca.lproj/
 * cs.lproj/
 * da.lproj/
 * el.lproj/
 * en_GB.iproj/
 * fi.lproj/
 * he.lproj/
 * hr.lproj/
 * hu.lproj/
 * id.lproj/
 * ko.lproj/
 * ms.lproj/
 * no.lproj/
 * pt.lproj/
 * th.lproj/
 * pt_PT.iproj/
 * tr.lproj/
 * ro.lproj/
 * uk.lproj/
 * ru.lproj/
 * vi.lproj/
 * sk.lproj/
 * zh_CN.lproj/
 * sv.lproj/
 * zh_TW.lproj/

Files

 * Default@2x~iphone.png
 * DefaultConfiguration.plist
 * Entitlements.plist
 * Info.plist
 * iOS Diagnostics
 * PkgInfo
 * ResourceRules.plist