Even though Microsoft has its own Windows Insider program for Windows 10 Mobile, there can never been enough help or feedback. That may be the reason behind a new app in the Windows Store called Trial Agent Lite, which is just for Microsoft's employees.
While the app can only be used by Microsoft workers, the listing is public. It states:
Lumia Insider is an app for joining in Lumia phones Consumer Trials testing. By installing the app and signing in with your email address you will be given the chance to improve the quality of Lumia phones by answering to surveys and other means of feedback collection. Application is intended only for internal Microsoft employees. You can join with any Lumia device model currently on the market running WP8 or higher.
Again, if you are not a Microsoft employee, this app won't actually work on your Lumia phone. However, it's always a good sign to see a company looking to gain as much feedback as they can on their products.