It looks like the Windows 10 Anniversary Update (1607) has a few builtin apps that weren't in 1511.
I don't have a clean install of 1511 in front of me to compare, but going from memory I think these appx packages are new in 1607: Microsoft.Messaging Microsoft.Advertising.Xaml Microsoft.Advertising.Xaml Microsoft.OneConnect Microsoft.StorePurchaseApp Microsoft.DesktopAppInstaller I assume that they are safe to remove, since they are removable, but I'd like to know what they are, in case they offer some functionality that I would like to keep. Is there a reference anywhere as to what each of these packages are for?
