By what mechanism does finder insert a space in an app's name?
That's handled by localization.

If you check the Info.plist, there's a key LSHasLocalizedDisplayName with a value of true.  That means that there are localized names for the application.  Localizations are stored in the app bundle in Contents/Resources.  Since I'm using English, I can look in /System/Library/CoreServices/NotificationCenter.app/Contents/Resources/en.lproj/InfoPlist.strings, and see the name of the app with the space in it.

Strings files are actually binary plists.  You can view them in a human-readable fashion with

$ plutil -p /System/Library/CoreServices/NotificationCenter.app/Contents/Resources/en.lproj/InfoPlist.strings
{
  "CFBundleDisplayName" =&gt; "Notification Center"
  "CFBundleName" =&gt; "Notification Center"
}