The Internal Product Testing category is private and a great way to collect feedback from everyone. People will need permission to be able to view and create topics in this.
For moderators and admins - Go to settings and create a user group that can be part of a user testing category in the beginning when the Product is in internal Alpha Testing.
We can make a category public in Beta Testing and anyone can use it.
Remember to remove the tag Internal Product Testing before Product when making it public.